SmarterEd

Aussie Maths & Science Teachers: Save your time with SmarterEd

CHEMISTRY, M2 2009 HSC 22

The nitrogen content of bread was determined using the following procedure:

    • A sample of bread weighing 2.80 g was analysed.
    • The nitrogen in the sample was converted into ammonia.
    • The ammonia was collected in 50.0 mL of 0.125 mol L\(^{-1}\) hydrochloric acid. All of the ammonia was neutralised, leaving an excess of hydrochloric acid.
    • The excess hydrochloric acid was titrated with 23.30 mL of 0.116 mol L\(^{-1}\) sodium hydroxide solution.
  1. Write balanced equations for the TWO reactions involving hydrochloric acid.  (2 marks)

  2. Calculate the moles of excess hydrochloric acid.  (1 mark)

  3. Calculate the moles of ammonia.   (2 marks)

  4. Calculate the percentage by mass of nitrogen in the bread.  (2 marks)

Show Answers Only

a.    \(\ce{NH3(g) + HCl(aq) \rightarrow NH4+(aq) + Cl-(aq)}\)

\(\ce{NaOH(aq) + HCl(aq) \rightarrow NaCl(aq) + H2O(l)}\)

b.   \(2.70 \times 10^{-3}\)

c.   \(3.55 \times 10^{-3}\)

d.   \(1.78\%\)

Show Worked Solution

a.   \(\ce{NH3(g) + HCl(aq) \rightarrow NH4+(aq) + Cl-(aq)}\)

\(\ce{NaOH(aq) + HCl(aq) \rightarrow NaCl(aq) + H2O(l)}\)
 

b.   \(\ce{n(NaOH excess) = c \times V = 0.116 \times 0.02330 = 2.70 \times 10^{-3} moles}\)
 

c.   \(\ce{n(HCl original) = c \times V = 0.125 \times 0.0500 = 6.25 \times 10^{-3} moles}\)

\(\ce{n(HCl used) = 6.25 \times 10^{-3}-2.70 \times 10^{-3} = 3.55 \times 10^{-3} moles}\)

\(\ce{n(NH3) = n(HCl used) = 3.55 \times 10^{-3} moles}\)
 

d.   \(\ce{n(N) = n(NH3) = 3.55 \times 10^{-3} moles}\)

\(\ce{Mass N = 3.55 \times 10^{-3} \times 14.01 = 0.0497 g}\)

\[\ce{\% N (by mass) = \frac{0.0497}{2.80} \times 100\% = 1.78\%}\]

CHEMISTRY, M2 2010 HSC 15 MC

What mass of ethanol \(\ce{C2H5OH}\) is obtained when 5.68 g of carbon dioxide is produced during fermentation, at 25°C and 100 kPa ?

\(\ce{C6H12O6 \rightarrow 2CO2 + 2C2H5OH}\)

  1. 2.95 g
  2. 5.95 g
  3. 33.6 g
  4. 147.2 g
Show Answers Only

\(B\)

Show Worked Solution

\(n(\ce{CO2})= \dfrac{5.68}{44.01} =0.129\ \text{mol} = n(\ce{C2H5OH})\)

\(m(\ce{C2H5OH})=0.129 \times 46.068 = 5.95\ \text{g}\)

\(\Rightarrow B\)

CHEMISTRY, M2 2010 HSC 31ai

A student collected a 250 mL sample of water from a local dam for analysis. The data collected are shown in the table.

\begin{array} {|l|r|}
\hline
\rule{0pt}{2.5ex}\text{Mass of filter paper}\rule[-1ex]{0pt}{0pt} & \text{0.23 g} \\
\hline
\rule{0pt}{2.5ex}\text{Mass of filter paper and solid}\rule[-1ex]{0pt}{0pt} & \text{0.47 g} \\
\hline
\rule{0pt}{2.5ex}\text{Mass of evaporating basin}\rule[-1ex]{0pt}{0pt} & \text{43.53 g} \\
\hline
\rule{0pt}{2.5ex}\text{Mass of basin and solid remaining}\ \ \rule[-1ex]{0pt}{0pt} & \text{44.67 g} \\
\hline
\end{array}

The water was filtered and the filtrate evaporated to dryness.

Calculate the percentage of the total dissolved solids in the dam sample.  (2 marks)

Show Answers Only

0.46%

Show Worked Solution

\(\text{Total Dissolved Solids}\ = 44.67-43.53 = 1.14\ \text{g}\)

\[\text{% TDS in sample}\ = \frac{1.14}{250} \times 100\% = 0.46\%\ \text{(to 2 d.p.)}\]

CHEMISTRY, M2 2012 HSC 5* MC

Which of the following is a balanced equation representing the fermentation of glucose?

  1. \(\ce{C6H12O6}(aq) \rightarrow \ce{C2H5OH}(aq) + \ce{CO2}(g)\)
  2. \(\ce{C6H12O6}(aq) \rightarrow \ce{2C2H5OH}(aq) + \ce{2CO2}(g)\)
  3. \(\ce{C6H12O6}(aq) \rightarrow \ce{C2H5OH}(aq) + \ce{2CO2}(g)\)
  4. \(\ce{2C6H12O6}(aq) \rightarrow \ce{4C2H5OH}(aq) + \ce{4CO2}(g)\)
Show Answers Only

\(B\)

Show Worked Solution

→ 1 glucose molecule undergoes fermentation to produce 2 ethanol molecules and 2 carbon dioxide molecules as seen in \(B\).

\(=>B\)

CHEMISTRY, M2 2013 HSC 4 MC

Butan-1-ol burns in oxygen according to the following equation.

\(\ce{C4H9OH(l)} + \ce{6O2(g)} \rightarrow \ce{4CO2(g)} + \ce{5H2O(l)} \)

How many moles of carbon dioxide would form if two moles of butan-1-ol were burnt in excess oxygen?

  1. 2
  2. 4
  3. 8
  4. 10
Show Answers Only

\(C\)

Show Worked Solution

\(n(\ce{CO2(g)})=4 \times n(\ce{C4H9OH(l)})\)

\(\Rightarrow C\)

CHEMISTRY, M1 2008 HSC 3 MC

Which term describes the relationship between oxygen and ozone?

  1. Allotropes
  2. Conjugates
  3. Isomers
  4. Isotopes
Show Answers Only

`A`

Show Worked Solution

→ Allotropes are different forms of the same element as a result of different structures and bonding. 

→ As both oxygen and ozone are made up of only oxygen atoms, they are called allotropes.

`=>A`

CHEMISTRY, M1 2009 HSC 1 MC

Which of the following is an important factor in predicting the nuclear stability of an isotope?

  1. Atomic radius
  2. Nuclear radius
  3. The ratio of neutrons to protons
  4. The ratio of electrons to protons
Show Answers Only

`C`

Show Worked Solution

→ Nuclear stability refers to the stability of the nucleus within the atom. 

→ As the nucleus is made up of protons and neutrons, it is the ratio of these particles which are an important factor in predicting nuclear stability.

`=>C`

CHEMISTRY, M1 2013 HSC 6 MC

A representation of the Periodic Table is shown. The positions of six different elements, \(P, Q, R, S, T\) and \(U\) are given.
 

Which row of the following table shows the correct acid and base reactivities of the oxides of these elements?
 

Show Answers Only

`A`

Show Worked Solution

→ Acidic Oxides: are often the oxides of non-metals and form acidic solutions

→ Basic Oxides: are usually formed by reacting oxygen with metals, they participate with acids in neutralisation rections

→ Neutral Oxides: react with neither acids or bases and do not lead to either acidic or basic solutions

→ Amphoteric Oxides: exhibit both acidic and basic properties, they can chemically react as either an acid or base

`=>A`

BIOLOGY, M4 2016 HSC 35c

  1. What are TWO features of chromosomes used in karyotype analysis?  (2 marks)

  2. Sketch a graph that depicts changes in human population over the last 10 000 years. Identify a point on the graph that shows the effect of a technological advance on world population.  (2 marks)

Show Answers Only

i.      → The position of centromeres.

→ The banding patterns present.
 

ii.    
       

Show Worked Solution

i.      → The position of centromeres

→ The banding patterns present.
 

ii.    
       

BIOLOGY, M3 2013 HSC 26

A virus was used to kill rabbits in Australia. After first release of the virus nearly all rabbits were killed, but over time the numbers recovered. 

Outline how Darwin/Wallace's theory of evolution could be used to explain the recovery of rabbit numbers.  (3 marks)

Show Answers Only

→ Darwin/Wallace’s theory of evolution suggests variation in a population and the fittest survive to pass on their characteristics.

→ When the virus emerged, it killed most of the rabbits, however, some rabbits would be resistant and survive.

→ The survivors reproduced and passed this characteristic (resistance) on to their offspring and as the population increased, most rabbits were then resistant to the virus.

Show Worked Solution

→ Darwin/Wallace’s theory of evolution suggests variation in a population and the fittest survive to pass on their characteristics.

→ When the virus emerged, it killed most of the rabbits, however, some rabbits would be resistant and survive.

→ The survivors reproduced and passed this characteristic (resistance) on to their offspring and as the population increased, most rabbits were then resistant to the virus.

BIOLOGY, M3 2016 HSC 22

Name an Australian ectotherm and describe its response to a decrease in ambient temperature.  (2 marks)

Show Answers Only

Answers can include:

→ The Eastern Brown Snake will bask in the sun when the ambient temperature falls.

→ Goannas can rapidly move their gular (throat) pouch which acts as a cooling mechanism.

Show Worked Solution

Answers can include:

→ The Eastern Brown Snake will bask in the sun when the ambient temperature falls.

→ Goannas can rapidly move their gular (throat) pouch which acts as a cooling mechanism.

BIOLOGY, M2 2015 HSC 24

Data can be provided by a pulse oximeter pegged to a person's finger, as shown in the diagram.

  1. What is the oxygen saturation for this person?  (1 mark)

  2. Outline TWO limitations of using only the information provided in the diagram to determine the 'health' of a person.  (2 marks)

  3. Explain TWO advantages in using a pulse oximeter to measure oxygen saturation compared to using another named technology in a specific setting.  (4 marks)

Show Answers Only

a.   97%
 

b.   Answers could include:

→ Data requires context (eg. is the user exercising or resting).

→ There are many other parameters of physical health: disease status, blood levels of toxic environmental substances, presence of cancers etc…

→ There are other aspects of non-physical health (eg. mental health).

→ The pulse oximeter could read faulty i.e. if not properly calibrated, so comparing with results from another form of test such as a blood pressure monitor would give a better indication of cardiorespiratory health.
 

c.   Answers could include:

→ The pulse oximeter can give you immediate and continuous data. This makes it better than arterial blood gas determination from a blood sample that requires the sample to be analysed in a laboratory with a delayed and one-off reading.

→ The pulse oximeter is very portable being compact and battery operated.

→ The pulse oximeter is better for an ambulance where fast and continuous data delivery in an emergency setting is required.

Show Worked Solution

a.   97%
 

b.   Answers could include:

→ Data requires context (eg. is the user exercising or resting).

→ There are many other parameters of physical health: disease status, blood levels of toxic environmental substances, presence of cancers etc…

→ There are other aspects of non-physical health (eg. mental health).

→ The pulse oximeter could read faulty i.e. if not properly calibrated, so comparing with results from another form of test such as a blood pressure monitor would give a better indication of cardiorespiratory health.
 

c.   Answers could include:

→ The pulse oximeter can give you immediate and continuous data. This makes it better than arterial blood gas determination from a blood sample that requires the sample to be analysed in a laboratory with a delayed and one-off reading.

→ The pulse oximeter is very portable being compact and battery operated.

→ The pulse oximeter is better for an ambulance where fast and continuous data delivery in an emergency setting is required.

BIOLOGY, M2 2016 HSC 27

The diagram shows a vascular bundle from a flowering plant.

  1. On the diagram, clearly label a xylem vessel.  (1 mark)
  2. A adaptation of this species causes the walls of the xylem vessels to be significantly reduced in thickness.
  3. Explain why the leaves of these adapted strains will wilt more easily.  (3 marks)

Show Answers Only

a.   
       

b.   → Leaves wilt when they lose water.

→ As xylem tissue is responsible for water transport from roots to leaves, plants with the adaptation will wilt easier as the xylem vessels are more likely to collapse with thinner walls.

Show Worked Solution

a.   
       

b.   → Leaves wilt when they lose water.

→ As xylem tissue is responsible for water transport from roots to leaves, plants with the adaptation will wilt easier as the xylem vessels are more likely to collapse with thinner walls.

BIOLOGY, M2 2016 HSC 21

Give TWO potential benefits of artificial blood.  (2 marks)

Show Answers Only

Answers can include:

→ It does not need to be refrigerated.

→ It does not require blood-type matching.

→ Can be a valid substitute for certain ethnic/cultural groups which have concerns surrounding blood products.

→ Does not require a donor.

Show Worked Solution

Answers can include:

→ It does not need to be refrigerated.

→ It does not require blood-type matching.

→ Can be a valid substitute for certain ethnic/cultural groups which have concerns surrounding blood products.

→ Does not require a donor.

CHEMISTRY, M5 EQ-Bank 21

Potassium chloride readily dissolves in water. With the use of a labelled diagram, describe the changes in bonding and entropy that occurs during this process.  (4 marks)

Show Answers Only

→ Potassium chloride has a high tendency to dissociate into \(\ce{K^+}\) and \(\ce{Cl^{-}}\) ions when mixed with water (i.e. it is highly soluble).

→ Water is a dipolar molecule because each atom has a partial charge, as shown in the diagram. 

→ The oxygen dipole in water has a partial negative charge and is attracted to the potassium ion. The hydrogen dipoles have a partial negative charge and are attracted to the chloride ion. 

→ This attraction breaks the ionic bonds and forms ion-dipole bonds.

→ The entropy of the system is increased as the ionic bonds of the \(\ce{KCl}\) are broken and the \(\ce{K^{+}}\) and \(\ce{Cl^{-}}\) ions disperse throughout the solution.

Show Worked Solution

→ Potassium chloride has a high tendency to dissociate into \(\ce{K^+}\) and \(\ce{Cl^{-}}\) ions when mixed with water (i.e. it is highly soluble).

→ Water is a dipolar molecule because each atom has a partial charge, as shown in the diagram. 

→ The oxygen dipole in water has a partial negative charge and is attracted to the potassium ion. The hydrogen dipoles have a partial negative charge and are attracted to the chloride ion. 

→ This attraction breaks the ionic bonds and forms ion-dipole bonds.

→ The entropy of the system is increased as the ionic bonds of the \(\ce{KCl}\) are broken and the \(\ce{K^{+}}\) and \(\ce{Cl^{-}}\) ions disperse throughout the solution.

CHEMISTRY, M6 EQ-Bank 3 MC

The structure of an organic compound is shown.
 

Which row of the table correctly shows how this compound reacts with bromine water and with blue litmus?
 

Show Answers Only

`D`

Show Worked Solution

→ Organic compound is sorbic acid.

→ Bromine water changes from a bright yellow to a colourless solution when it reacts with sorbic acid.

→ The acidic nature of the organic compound will turn blue litmus red.

`=>D`

CHEMISTRY, M5 EQ-Bank 22

Hydrogen gas reacts with iodine gas to form hydrogen iodide according to the following equation.

\( \ce{H2(g) + I2(g) \rightleftharpoons 2HI(g)}\) at 700 k

At equilibrium, the concentrations for \(\ce{H2, I2}\) and \(\ce{HI}\) are as follows:  0.326 mol L–1, 0.326 mol L–1 and 2.39 mol L–1 respectively.

What is the value of the equilibrium constant for this reaction?  (2 marks)

Show Answers Only

53.7

Show Worked Solution

\[\ce{$K_{eq}$ = \frac{[HI]^2}{[H2][I2]} = \frac{2.39^2}{[0.326][0.326]} = 53.7}\]

CHEMISTRY, M5 EQ-Bank 3 MC

Consider the following reaction.

\( \ce{2NOCl(g) \rightleftharpoons 2NO(g) + Cl2(g)}\).

What is the equilibrium expression for this reaction?

  1. `(2[\text{NO}][\text{Cl}_2])/(2[\text{NOCl}])`
  2. `([\text{NO}]^(2)[\text{Cl}_2])/([\text{NOCl}]^(2))`
  3. `(2[\text{NOCl}])/(2[\text{NO}][\text{Cl}_2])`
  4. `([\text{NOCl}]^2)/(2[\text{NO}]^2[\text{Cl}_2])`
Show Answers Only

`B`

Show Worked Solution

→ All elements in the reaction are included in the \(\ce{$K_{eq}$}\) expression (i.e. no solids or pure liquids are present which would be omitted)

\[\ce{$K_{eq}$ = \frac{[NO]^2[Cl2]}{[NOCl]^2}} \]

`=>B`

CHEMISTRY, M5 EQ-Bank 21

Three gases \(\ce{X, Y}\) and \(\ce{Z}\) were mixed in a closed container and allowed to reach equilibrium. A change was imposed at time \(\ce{$T$}\) and the equilibrium was re-established. The concentration of each gas is plotted against time.
 

  1. What is a possible change that was imposed at time \(\ce{$T$}\)?  (1 mark)

  2. Write a chemical reaction that is represented by the concentration graph above.  (2 marks)

Show Answers Only
  1. An increase in the volume of the container.
  2. \( \ce{X(g) \rightleftharpoons Y(g) + Z(g)}\)
Show Worked Solution

a.   At time \(\ce{$T$}\):

→ The concentration of all species decreases by an amount proportional to their initial concentration.

→ This could be due to an increase in the volume of the container.

 

b.   Chemical reaction:

→ After the system change, equilibrium re-establishes by favouring the conversion of \(\ce{X}\) into \(\ce{Y}\) and \(\ce{Z}\) .

→ As change in concentration of all species is equal, they react in a 1:1:1 molar ratio.

→ Therefore the chemical reaction is:  \( \ce{X(g) \rightleftharpoons Y(g) + Z(g)}\)

CHEMISTRY, M7 EQ-Bank 23

  1. Design a procedure that can be used to produce the ester, ethyl ethanoate, in a school laboratory.   (4 marks)

  2. Describe a safety precaution in the production of an ester in a school laboratory.   (2 marks)

Show Answers Only

a.   Methodology:

STEP 1: Reflux equipment using a hot plate heating source.

STEP 2: Pour 10 mL of ethanol into a round bottom flask. Add 20 mL of glacial (water-free) acetic acid.

STEP 3: Add 1 mL of concentrated \(\ce{H2SO4}\) (sulfuric acid) to the mixture. Boiling stones/chips can be added to smooth the boiling process before heating under reflux for 45 minutes.

STEP 4: Allow the solution to cool. The contents should then be transferred to a separating funnel.

STEP 5: Distilled water should be used to wash the contents which will remove excess alcohol and acetic acid. The ester layer has a density less than 1 g/mL and will therefore form a layer above the aqueous solution.

STEP 5: Remove the aqueous solution using the separating funnel.

STEP 6: By adding a solution of 1 mol L ¯1  \(\ce{Na2CO3}\) (sodium carbonate), all remaining acid will be removed. Similarly to Step 4, the ester can be isolated by removing the lower layer of aqueous solution using the separating funnel.
 

b.    → Ethanol presents a danger due to its combustibility.

→ A safety precaution that reduces the fire threat is through the use of a hot plate for heating rather than a naked flame.

Show Worked Solution

a.   Methodology:

STEP 1: Reflux equipment using a hot plate heating source.

STEP 2: Pour 10 mL of ethanol into a round bottom flask. Add 20 mL of glacial (water-free) acetic acid.

STEP 3: Add 1 mL of concentrated \(\ce{H2SO4}\) (sulfuric acid) to the mixture. Boiling stones/chips can be added to smooth the boiling process before heating under reflux for 45 minutes.

STEP 4: Allow the solution to cool. The contents should then be transferred to a separating funnel.

STEP 5: Distilled water should be used to wash the contents which will remove excess alcohol and acetic acid. The ester layer has a density less than 1 g/mL and will therefore form a layer above the aqueous solution.

STEP 5: Remove the aqueous solution using the separating funnel.

STEP 6: By adding a solution of 1 mol L ¯1  \(\ce{Na2CO3}\) (sodium carbonate), all remaining acid will be removed. Similarly to Step 4, the ester can be isolated by removing the lower layer of aqueous solution using the separating funnel.
 

b.    → Ethanol presents a danger due to its combustibility.

→ A safety precaution that reduces the fire threat is through the use of a hot plate for heating rather than a naked flame.

CHEMISTRY, M8 EQ-Bank 27

Explain how infrared spectroscopy is used in the analysis and identification of organic substances.   (3 marks)

Show Answers Only

→ When analysing organic substances, IR radiation of specific wavelengths will be absorbed by certain atoms of the organic molecules. The absorption is dependent on the length of the compound’s atomic bonds.

→ By utilising the complete IR spectrum, the particular bonds in a molecule can be identified. The degree of the absorption can be used to calculate the relative number of each specific bond.

→ The resulting absorption data can be used to create an absorption spectrum of the organic material. This spectrum can then be compared to published data and used to identify the organic material.

Show Worked Solution

→ When analysing organic substances, IR radiation of specific wavelengths will be absorbed by certain atoms of the organic molecules. The absorption is dependent on the length of the compound’s atomic bonds.

→ By utilising the complete IR spectrum, the particular bonds in a molecule can be identified. The degree of the absorption can be used to calculate the relative number of each specific bond.

→ The resulting absorption data can be used to create an absorption spectrum of the organic material. This spectrum can then be compared to published data and used to identify the organic material.

CHEMISTRY, M8 EQ-Bank 22

  1. The diagram is a schematic representation of a mass spectrometer.
     

  1. Name and outline the function of the part labelled `A` in the diagram.   (2 marks)

  2. Outline the advantages of using mass spectrometry for analysis of a compound.   (3 marks)

Show Answers Only

a.    → \(\ce{A}\) is a magnet.

→ It bends the charged particles that are accelerated through an electric field and directed through it.

→ The amount of bending can then be used to distinguish between and identify the particles/ions.
 

b.   Advantages of mass spectrometry

→ The mass spectrometer can identify the mass/charge ratio of ions that pass through it. This data can then be used to identify components of a mixture or components in a compound.

→ Different isotopes of elements in a compound can be identified by mass spectrometers. This allows the compound to be matched to a sample.

→ Mass spectrometry can provide both qualitative and quantitative data on a compound.

→ Finally, mass spectrometers only require a small quantity of a compound to perform detailed analysis, as well as being fast and sensitive.

Show Worked Solution

a.    → \(\ce{A}\) is a magnet.

→ It bends the charged particles that are accelerated through an electric field and directed through it.

→ The amount of bending can then be used to distinguish between and identify the particles/ions.
 

b.   Advantages of mass spectrometry

→ The mass spectrometer can identify the mass/charge ratio of ions that pass through it. This data can then be used to identify components of a mixture or components in a compound.

→ Different isotopes of elements in a compound can be identified by mass spectrometers. This allows the compound to be matched to a sample.

→ Mass spectrometry can provide both qualitative and quantitative data on a compound.

→ Mass spectrometers only require a small quantity of a compound to perform detailed analysis, as well as being fast and sensitive.

CHEMISTRY, M8 EQ-Bank 21

The diagram shows the deflection paths of different ions through a mass spectrometer.
 

Account for the different deflection paths.   (3 marks)

Show Answers Only

→ Mass spectrometers use an electric field to accelerate positively charged ions before passing them through a magnetic field.

→ Once in the magnetic field, the ions travel in a curved path, the direction of which depends on whether the ion is positively or negatively charged.

→ The amount of curvature is dependent on the speed at which the ion is travelling and its mass to charge ratio.

→ Lighter ions have less momentum and are deflected more strongly than heavier ions.

Show Worked Solution

→ Mass spectrometers use an electric field to accelerate positively charged ions before passing them through a magnetic field.

→ Once in the magnetic field, the ions travel in a curved path, the direction of which depends on whether the ion is positively or negatively charged.

→ The amount of curvature is dependent on the speed at which the ion is travelling and its mass to charge ratio.

→ Lighter ions have less momentum and are deflected more strongly than heavier ions.

CHEMISTRY, M5 EQ-Bank 4 MC

Particle reacts with particle to form the molecule . The system comes to an equilibrium.

The diagram shows the initial reactants.
 

Which combination of diagrams best represents the molecule in a dynamic equilibrium and a static equilibrium?
 

Show Answers Only

`A`

Show Worked Solution

→ In dynamic state, some particles have not yet combined to form a molecule.

→ In static state, all particles that could react have formed molecules.

`=>A`

PHYSICS, M7 EQ-Bank 21

  1. A student was given a smartphone with a light sensor and an angle sensor, and a computer screen which emitted polarised light. A polariser was fixed over the top of the light sensor in the smartphone.
     

  1. The student wants to use this equipment to investigate Malus's Law of polarised light. Describe a procedure that is suitable for carrying out this investigation.  (3 marks)
  1. An experiment was conducted to demonstrate Malus's Law for plane polarisation of light. The results are shown in the graph.
     

  1. Based on the graph shown, how effective was the experiment in meeting its aim?  (3 marks)
Show Answers Only

a.   Procedure steps:

→ Secure the smartphone so it can rotate at a measured and fixed distance from the computer screen.

→ Set the computer to emit a constant intensity of light.

→ Find the position of the smartphone at which light of maximum intensity is obtained. Set this position to be 0° and record the intensity.

→ Rotate the smartphone through 360° and record the intensity at regular intervals of 10°.

→ Plot obtained results on a graph.
 

b.    → Malus’ Law gives the equation  `I=I_(max)cos^2theta`

→ The graph shape that is produced by the experimental data is consistent with the equation. 

→ The experiment uses a sufficient range of data to show a relationship and uses a sufficient number of data points.

→ However, the equipment used must have been incorrectly calibrated, or the measurements were not taken correctly. Measurements appear to be offset by 30° as the maximum intensity of light should occur at 0° rather than 30°. 

Show Worked Solution

a.   Procedure steps:

→ Secure the smartphone so it can rotate at a measured and fixed distance from the computer screen.

→ Set the computer to emit a constant intensity of light.

→ Find the position of the smartphone at which light of maximum intensity is obtained. Set this position to be 0° and record the intensity.

→ Rotate the smartphone through 360° and record the intensity at regular intervals of 10°.

→ Plot obtained results on a graph.
 

b.    → Malus’ Law gives the equation  `I=I_(max)cos^2theta`

→ The graph shape that is produced by the experimental data is consistent with the equation. 

→ The experiment uses a sufficient range of data to show a relationship and uses a sufficient number of data points.

→ However, the equipment used must have been incorrectly calibrated, or the measurements were not taken correctly. Measurements appear to be offset by 30° as the maximum intensity of light should occur at 0° rather than 30°. 

PHYSICS, M7 EQ-Bank 3 MC

A spaceship sitting on its launch pad is measured to have a length `L`. This spaceship passes an outer planet at a speed of 0.95`c`.

Which observations of the length of the spaceship are correct?
 

Show Answers Only

`A`

Show Worked Solution

→ An observer in the frame of reference of the spaceship will measure the proper length of the spaceship.

→ An observer on the planet will observe relativistic length contraction and will observe the length to be shorter than `L`.

`=>A`

PHYSICS, M7 EQ-Bank 1 MC

In which of the following areas of physics did James Clerk Maxwell NOT contribute to our understanding?

  1. The unification of electricity and magnetism through equations.
  2. Predicting light is a form of electromagnetic radiation.
  3. Predicting the velocity of electromagnetic waves
  4. Validating the existence of electromagnetic waves
Show Answers Only

`D`

Show Worked Solution

→ Maxwell’s contributions to our understanding of electromagnetism were only theoretical.

→ Maxwell used equations to predict the existence and properties of electromagnetic waves, however, never experimentally validated their existence.

`=>D`

PHYSICS, M6 EQ-Bank 21

A current of 4.0 A flows in a wire that is placed in a magnetic field of 0.75 T. The wire is 0.80 m long and is at an angle of 45° to the field.
 


 

Calculate the force on the wire.  (2 marks)

Show Answers Only

`1.7\ text{N out of the page.}`

Show Worked Solution
`F` `=lIB sin theta`  
  `=0.8 xx4.0 xx0.75 xx sin 45^(@)`  
  `=1.7\ text{N out of the page.}`  

PHYSICS, M6 EQ-Bank 24

Negatively charged particles were accelerated from rest between a pair of parallel metal plates. The potential difference between the plates was varied, and the final velocity of the particles was measured for each variation.
 

The data in the table show the potential difference between the plates and the square of the corresponding final velocity of the particles.

\begin{array}{|c|c|}
\hline
\rule{0pt}{2.5ex}\textit{Potential difference}\ \text{(V)} \rule[-1ex]{0pt}{0pt}&\quad v^2\left(\times 10^9 \, \text{m}^2\, \text{s}^{-2}\right) \quad \\
\hline
\rule{0pt}{2.5ex}100\rule[-1ex]{0pt}{0pt}&0.8\\
\hline
\rule{0pt}{2.5ex}200\rule[-1ex]{0pt}{0pt}& 2.1\\
\hline
\rule{0pt}{2.5ex}300\rule[-1ex]{0pt}{0pt}& 3.1 \\
\hline
\rule{0pt}{2.5ex}400\rule[-1ex]{0pt}{0pt}& 4.1 \\
\hline
\rule{0pt}{2.5ex}500\rule[-1ex]{0pt}{0pt}& 5.2 \\
\hline
\end{array}

  1. Plot the data on the grid provided and draw a line of best fit.
     

   

  1. A student hypothesised that the charged particles are electrons. Justify whether the student's hypothesis is correct or not. Support your answer using the data provided and relevant calculations.
Show Answers Only

a.   
         

     

b.    → The gradient of the line = `(v^2)/(V)`

→ Calculate the gradient using two points on the line of best fit (choose values close to limits):

`text{gradient}` `=((5.2-0.9) xx10^(9))/(500-100)`  
  `=1.1 xx10^7  text{m}^2  text{s}^(-2)  text{V}^(-1)`  

 
→ The change in kinetic energy is equal to the work done by the electric field on the charged particles:

`W` `=Delta K`  
`qV` `=(1)/(2)mv^2`  
`(V^2)/(v)` `=(2q)/(m)`  

 
→ Calculate the charge to mass ratio of the particles:

`(q)/(m)` `=(V^2)/(2v)`  
  `=(text{gradient})/(2)`  
  `=5.4 xx10^6  text{C kg}^(-1)`  

 
 → Calculate the charge to mass ratio of an electron:

`(q)/(m)` `=(1.602 xx10^(-19))/(9.109 xx10^(-31))`  
  `=1.8 xx10^(11)  text{C kg}^(-1)`  

  
→ Therefore, the charged particles are not electrons.

Show Worked Solution

a.   
         

     

b.    → The gradient of the line = `(v^2)/(V)`

→ Calculate the gradient using two points on the line of best fit (choose values close to limits):

`text{gradient}` `=((5.2-0.9) xx10^(9))/(500-100)`  
  `=1.1 xx10^7  text{m}^2  text{s}^(-2)  text{V}^(-1)`  

 
→ The change in kinetic energy is equal to the work done by the electric field on the charged particles:

`W` `=Delta K`  
`qV` `=(1)/(2)mv^2`  
`(V^2)/(v)` `=(2q)/(m)`  

 
→ Calculate the charge to mass ratio of the particles:

`(q)/(m)` `=(V^2)/(2v)`  
  `=(text{gradient})/(2)`  
  `=5.4 xx10^6  text{C kg}^(-1)`  

 
 → Calculate the charge to mass ratio of an electron:

`(q)/(m)` `=(1.602 xx10^(-19))/(9.109 xx10^(-31))`  
  `=1.8 xx10^(11)  text{C kg}^(-1)`  

  
→ Therefore, the charged particles are not electrons.

PHYSICS, M6 EQ-Bank 22

An 'electron gun' like that used by JJ Thomson is shown.
 

Electrons leave the cathode and are accelerated towards the anode.

  1. Show that the acceleration of the electrons as they just leave the cathode is  `4 × 10^(16) \ text{m s}^(-2)`.   (2 marks)
  1. Calculate the velocity of an electron as it reaches the anode.   (2 marks)
Show Answers Only
  1. `4 xx10^(16)  text{m s}^(-2)`
  2. `4 xx10^7  text{m s}^(-1)`
Show Worked Solution

a.   The force on the electrons is given by  `F=qE`.

The electric field strength is given by  `E=(V)/(d)`:

`F` `=(Vq)/(d)`  
`a` `=(F)/(m)`  
  `=(Vq)/(dm)`  

 
Calculate the acceleration:

`a` `=(Vq)/(dm)`  
  `=(5000 xx1.602 xx10^(-19))/(0.02 xx9.109 xx10^(-31))`  
  `=4 xx10^(16)  text{m s}^(-2)`  

 

b.    Using kinematic equations:

`v^(2)` `=u^(2)+2as`  
`v` `=sqrt(2as),\ \ \ (u=0)`  
  `=sqrt(2xx4xx10^(16)xx0.02)`  
  `=4 xx10^7  text{m s}^(-1)`   

PHYSICS, M6 EQ-Bank 2 MC

What is the role of a transformer at a power station?

  1. To reduce heating in the transmission lines by stepping up the current
  2. To reduce heating in the transmission lines by stepping up the voltage
  3. To increase heating in the transmission lines by stepping up the current
  4. To increase heating in the transmission lines by stepping up the voltage
Show Answers Only

`B`

Show Worked Solution

→ At a power station, heating is reduced to decrease power loss.

→ This is done by stepping up the voltage, which decreases transmission current and lowers heating loss consistent with  `P_(loss)=I^2R`

`=>B`

PHYSICS, M6 EQ-Bank 2 MC

A student performed an experiment using two identical, current-carrying metal rods connected to a power supply. Rod `A` was placed at different distances from Rod `B`, and the measurements on the electronic balance were recorded.
 

What is the dependent variable in this experiment?

  1. The current in `A`
  2. The length of the rods
  3. The mass recorded on the balance
  4. The distance between the two rods
Show Answers Only

`C`

Show Worked Solution

→ The dependent variable is the variable which is being measured.

→ In this experiment, the mass recorded on the balance is measured.

`=>C`

BIOLOGY, M8 EQ-Bank 14

  1. Identify a disorder or disease, and describe how it affects the normal function of an organ.   (2 marks)

  2. Evaluate the effectiveness of a technology in managing the disorder or disease described in part (a).   (4 marks)

Show Answers Only

a.   Polycystic kidney disease

→ A disease in which cysts grow in the kidney.

→ This interferes with filtration and overtime, adversely affects the overall function of the kidney.
 

Other disorders/disease can include

→ Astigmatism, myopia or hyperopia.

→ Single sided deafness, hearing loss.
  

b.   Use of technology in treating polycystic kidney disease

→ Polycystic kidney disease will often progress in patients until kidney failure has occurred.

→ When 80% of kidney function is lost and a transplant cannot be found, dialysis is often the only viable option.

→ There are two types of dialysis, both of which replace the function of the kidney and clean the blood.

    • Haemodialysis is where blood is removed from the body and passed through a dialysis machine. The main component of the machine runs a special fluid known as dialysate countercurrent to the blood next to a permeable membrane. This allows the blood to effectively remove the toxins into the dialyse by diffusion. While this is extremely effective, it involves multiple visits per week and is very time consuming for the patients.
       
    • Peritoneal dialysis involves the flushing of dialysate directly into the abdominal cavity through a catheter. The peritoneal membrane then acts as the filter and blood is cleaned via diffusion. The dialysate containing the waste products then exits the body into another section of the catheter. In contrast to haemodialysis, this method requires a more involved initial surgery but provides the benefit of patients being able to do this by themselves at night.

→ Both forms of dialysis are extremely effective in replacing kidney function. Despite being time consuming and uncomfortable, they allow patients suffering from polycystic kidney disease to survive for extended periods, during which a transplant may become available.
 

Other technologies can include

→ Glasses.

→ Any form of hearing aid dependent on the ear disease/disorder, including standard hearing aids, bone conduction implants or cochlear implant.

Show Worked Solution

a.   Polycystic kidney disease

→ A disease in which cysts grow in the kidney.

→ This interferes with filtration and overtime, adversely affects the overall function of the kidney.
 

Other disorders/disease can include

→ Astigmatism, myopia or hyperopia.

→ Single sided deafness, hearing loss.
  

b.   Use of technology in treating polycystic kidney disease

→ Polycystic kidney disease will often progress in patients until kidney failure has occurred.

→ When 80% of kidney function is lost and a transplant cannot be found, dialysis is often the only viable option.

→ There are two types of dialysis, both of which replace the function of the kidney and clean the blood.

    • Haemodialysis is where blood is removed from the body and passed through a dialysis machine. The main component of the machine runs a special fluid known as dialysate countercurrent to the blood next to a permeable membrane. This allows the blood to effectively remove the toxins into the dialyse by diffusion. While this is extremely effective, it involves multiple visits per week and is very time consuming for the patients.
       
    • Peritoneal dialysis involves the flushing of dialysate directly into the abdominal cavity through a catheter. The peritoneal membrane then acts as the filter and blood is cleaned via diffusion. The dialysate containing the waste products then exits the body into another section of the catheter. In contrast to haemodialysis, this method requires a more involved initial surgery but provides the benefit of patients being able to do this by themselves at night.

→ Both forms of dialysis are extremely effective in replacing kidney function. Despite being time consuming and uncomfortable, they allow patients suffering from polycystic kidney disease to survive for extended periods, during which a transplant may become available.
 

Other technologies can include

→ Glasses.

→ Any form of hearing aid dependent on the ear disease/disorder, including standard hearing aids, bone conduction implants or cochlear implant.

BIOLOGY, M7 EQ-Bank 23

The diagram shows the immune response after primary exposure to a pathogen.
 

  1. On the diagram, continue the graph to show the immune response upon secondary exposure to the same pathogen.   (2 marks)
  2. Using annotations on the diagram, explain the shape of the entire graph.   (4 marks)

Show Answers Only

a. & b.

Show Worked Solution

a. & b.

BIOLOGY, M8 EQ-Bank 5 MC

Which of the following is an example of an educational program to reduce the incidence of skin cancer?

  1. An advertising campaign on TV to promote sun safety
  2. Making sunscreen freely available at pools and beaches
  3. Increasing the availability of free skin checks
  4. Providing free training to doctors to help them diagnose skin cancers
Show Answers Only

`A`

Show Worked Solution

By Elimination

→ Options C and D primarily increase the chances of diagnosing skin cancer rather than constituting an educational program.

→ Making sunscreen freely available will reduce the risk of skin cancer but is not an educational campaign.

→ The advertising campaign promotes safe lifestyle decisions surrounding sun safety (e.g. the benefits of using sunscreen, wearing a hat) that will reduce the likelihood of individuals getting skin cancer when following the advice.

`=>A`

BIOLOGY, M8 EQ-Bank 4 MC

An investigation was undertaken to examine the cause of lactose intolerance, a non-infectious condition found in some humans who cannot digest milk. The investigation found variation in the occurrence of lactose intolerance in human populations from different parts of the world.

What is this investigation an example of?

  1. A study of ecosystems
  2. A microbiological study
  3. An epidemiological study
  4. A study of the human immune system
Show Answers Only

`=>C`

Show Worked Solution

→ An epidemiological study is one which studies diseases which affect many people by gathering and analysing a large collection of data related to incidence and mortality, while comparing it to varying factors, such as location and age.

`=>C` 

BIOLOGY, M8 EQ-Bank 1 MC

What is the main focus of the study of epidemiology?

  1. Skin diseases
  2. Changes in the characteristics of a species
  3. Factors involved in the occurrence, prevalence and spread of disease
  4. How the body maintains its functions in response to variations in the environment
Show Answers Only

`C`

Show Worked Solution

→ The nature of an epidemiological study reveals evidence for factors involved in disease incidence and mortality.

`=>C`

BIOLOGY, M8 EQ-Bank 2 MC

The diagram shows a homeostatic mechanism in a mammal.
 

Which row of the table describes what happens to the muscles and the arteriole walls in the skin when the core body temperature is below normal?
 

Show Answers Only

`B`

Show Worked Solution

→ When the body is cold, it contracts to raise epidermal hairs (also known as goosebumps) which generates heat, closes skin pores and traps a layer of heat close to the skin.

→ The contraction of arteries (also known as vasoconstriction) helps conserve heat by minimising heat loss from the skin.

`=>B`

BIOLOGY, M7 EQ-Bank 12

A practical investigation is to be carried out to test for the microbes found in food.

Complete the table to show how to minimise risks that are likely to arise in carrying out this investigation.   (3 marks)
 

Show Answers Only

\begin{array} {|l|l|l|}
\hline \textit{Risk} & \textit{Procedure to minimise it} \\
\hline \text{Infection} & \text{Wear gloves.} \\
\hline \text{Growth of pathogenic} & \text{Incubate < 35° to prevent these microbes from growing.} \\
\hline \text{Cross-contamination} & \text{Sanitise bench and equipment.} \\
\hline \end{array}

Show Worked Solution

\begin{array} {|l|l|l|}
\hline \textit{Risk} & \textit{Procedure to minimise it} \\
\hline \text{Infection} & \text{Wear gloves.} \\
\hline \text{Growth of pathogenic} & \text{Incubate < 35° to prevent these microbes from growing.} \\
\hline \text{Cross-contamination} & \text{Sanitise bench and equipment.} \\
\hline \end{array}

BIOLOGY, M7 EQ-Bank 2 MC

The runny nose and coughing that is symptomatic of having a cold is an example of the body's response to a pathogen.

How does this response protect the body?

  1. By heating the body to try to kill the virus
  2. By trying to spread the virus to other people
  3. By preventing the virus from entering the body
  4. By attempting to rapidly expel the virus from the airways
Show Answers Only

`D`

Show Worked Solution

→ These symptoms are the body’s response to many illnesses and are methods to remove the virus from airways.

`=>D`

BIOLOGY, M6 EQ-Bank 22

The flow chart illustrates the effect of a point mutation on an organism.
 

  1. Outline the series of events from stages 2 to 4 that resulted in the faulty protein.   (3 marks)

  2. Describe how a type of mutagen may have caused the changes observed in stage 2.   (2 marks)

  3. Given the information in the chart shown, describe the effect caused by the mutation in stage 4 and the effect this would have on the organism.   (3 marks)
     
     

Show Answers Only

a.    → Stage 2: A mutagen causes a point mutation in the DNA.

→ Stage 3: The mutated DNA transcription into mRNA.

→ Stage 4: The translation of the mRNA into a polypeptide chain which is not functional due to the mutation.

 

b.    Possible causes of Stage 2 observed changes:

→ High frequency photons including gamma and X-rays are regarded as ionising radiation due to their extremely high energy.

→ They can interfere with DNA undergoing replication causing misalignment and a possible substation change.

→ High energy gamma radiation may also cause mutation when directly striking a nitrogenous base.  

 
Answers could also include

→ Chemical mutagens (alkylating, delaminating and structurally similar chemicals).

→ Carcinogenic metals/elements (radon, cadmium)
 

c.   Effects of Stage 4 mutation

→ When considering the above sequence as 2 codons, the chart shows us that this mutation results in an arginine amino becoming a stop codon.

→ This mutation will hence cause a premature termination of the polypeptide and result in a non-functional polypeptide/protein it forms a part of.

→ Due to the severity of this type of mutation it usually results in extensive health complications for affected individuals.

Show Worked Solution

a.    → Stage 2: A mutagen causes a point mutation in the DNA.

→ Stage 3: The mutated DNA transcription into mRNA.

→ Stage 4: The translation of the mRNA into a polypeptide chain which is not functional due to the mutation.

 

b.    Possible causes of Stage 2 observed changes:

→ High frequency photons including gamma and X-rays are regarded as ionising radiation due to their extremely high energy.

→ They can interfere with DNA undergoing replication causing misalignment and a possible substation change.

→ High energy gamma radiation may also cause mutation when directly striking a nitrogenous base.  

 
Answers could also include

→ Chemical mutagens (alkylating, delaminating and structurally similar chemicals).

→ Carcinogenic metals/elements (radon, cadmium)
 

c.   Effects of Stage 4 mutation

→ When considering the above sequence as 2 codons, the chart shows us that this mutation results in an arginine amino becoming a stop codon.

→ This mutation will hence cause a premature termination of the polypeptide and result in a non-functional polypeptide/protein it forms a part of.

→ Due to the severity of this type of mutation it usually results in extensive health complications for affected individuals.

BIOLOGY, M6 EQ-Bank 3 MC

A New Zealand research team inserted a single gene into an onion to reduce the activity of the enzyme that makes your eyes water, resulting in an onion that you can cut without crying.

Which term best describes this team's process?

  1. Cloning
  2. Artificial pollination
  3. Genetic engineering
  4. Artificial insemination
Show Answers Only

`C`

Show Worked Solution

→ Manually altering an organisms genome (such as in transgenic organisms) is referred to as genetic engineering.

`=>C`

BIOLOGY, M6 EQ-Bank 1 MC

A student was doing a literature review on biotechnology and wanted to see how biotechnology research could positively benefit people who suffered from Type 1 diabetes. He found several potential measures that were being explored to help people with diabetes.

Which of the following measures does NOT use biotechnology?

  1. Gene therapy in which genetic information is introduced into the cells of the pancreas
  2. The screening of genes to inform potential parents of the risk of their child developing Type 1 diabetes
  3. The use of auto-monitoring insulin pumps that can detect when a patient's insulin levels are dropping too low
  4. Collecting survey data on the prevalence of Type 1 diabetes in different communities to ensure insulin supplies are maintained at sufficient levels
Show Answers Only

`D`

Show Worked Solution

By Elimination

→ Gene therapy, auto monitoring insulin and screening and all examples of biotechnology. Option D is an epidemiological study (Eliminate A, B and C).

`=>D`

BIOLOGY, M5 EQ-Bank 24

A non-infectious disease was observed in a mother and her four sons who live with her. She has no daughters. The father of these children does not have the disease and does not live with them. The woman's parents and her two sisters who live overseas do not have the disease.

A geneticist suspects that the disease is inherited.

  1. Draw the family pedigree for this disease.   (3 marks)
     

     
  2. From the evidence, what indicates that the disease could be the result of a recessive allele and not be sex-linked?   (2 marks)

Show Answers Only

a.   
         
 

b.   Evidence disease is recessive and not sex-linked:

→ Generation 1 parents do not have the disease but it is present in their daughter, meaning it must be recessive.

→ If the disease was sex-linked, the same daughter who has the disease must have a father with the disease, however this is not the case.

Show Worked Solution

a.   
         
 

b.   Evidence disease is recessive and not sex-linked:

→ Generation 1 parents do not have the disease but it is present in their daughter, meaning it must be recessive.

→ If the disease was sex-linked, the same daughter who has the disease must have a father with the disease, however this is not the case.

BIOLOGY, M5 EQ-Bank 21

There are some significant differences in the form that DNA has in prokaryotic and eukaryotic cells.

In the space provided draw a labelled diagram demonstrating the difference in the form of DNA between prokaryotic and eukaryotic cells.   (3 marks)
 

Show Answers Only

Show Worked Solution

Points to note on images:

→ Prokaryotic DNA is in the form of a loop

→ Eukaryotic DNA has two loose ends and is tightly coiled in the body

BIOLOGY, M5 EQ-Bank 23

Students conducted preliminary experiments to analyse the DNA base composition of five different individuals.

The table shows the experimental data collected.
 

  1. On the grid provided, plot the % Guanine against % Adenine of the individuals analysed and draw a suitable line of best fit.   (3 marks)
     
     

  2. Identify the relationship shown by the data.   (1 mark)

  3. Explain the relationship shown by the data.   (3 marks)

Show Answers Only

a.   
       

b.  Relationship: As the % of Adenine increases, the % of Guanine decreases.

c.   Adenine/Guanine relationship

→ Because Adenine pairs with Thymine and Cytosine pairs with Guanine occurring to DNA base pairing rules, each should directly correlate to each other and account for the same % within the DNA composition of any species.

→ There are the only 4 components that make up all DNA composition. This also means that when comparing % of bases that do not pair, such as Adenine and Guanine, they must combine to form 50% of all DNA. This is evident when looking at individuals A and B, as well as C, D and E which are only off by 1-2%, most likely due to human error.

→ This always explains the relationship where an increase in Adenine (and Thymine) % will result in a decrease in Guanine (and Cytosine) % as the A and T pairs now occupy more space in the genome.

Show Worked Solution

a.   
       

b.  Relationship: As the % of Adenine increases, the % of Guanine decreases.

c.   Adenine/Guanine relationship

→ Because Adenine pairs with Thymine and Cytosine pairs with Guanine occurring to DNA base pairing rules, each should directly correlate to each other and account for the same % within the DNA composition of any species.

→ There are the only 4 components that make up all DNA composition. This also means that when comparing % of bases that do not pair, such as Adenine and Guanine, they must combine to form 50% of all DNA. This is evident when looking at individuals A and B, as well as C, D and E which are only off by 1-2%, most likely due to human error.

→ This always explains the relationship where an increase in Adenine (and Thymine) % will result in a decrease in Guanine (and Cytosine) % as the A and T pairs now occupy more space in the genome.

BIOLOGY, M5 EQ-Bank 22

  1. The following data shows the average amount of Human Chorionic Gonadotropin (hCG) produced by pregnant women.
      
    \begin{array}{|c|c|}
    \hline \rule{0pt}{2.5ex}\text {Weeks of pregnancy} \rule[-1ex]{0pt}{0pt} & h C G\,\text{(ng/mL)} \\
    \hline \rule{0pt}{2.5ex}0 \rule[-1ex]{0pt}{0pt}& 0 \\
    \hline \rule{0pt}{2.5ex}4 \rule[-1ex]{0pt}{0pt}& 85 \\
    \hline \rule{0pt}{2.5ex}8 \rule[-1ex]{0pt}{0pt}& 185 \\
    \hline \rule{0pt}{2.5ex}12 \rule[-1ex]{0pt}{0pt}& 185 \\
    \hline \rule{0pt}{2.5ex}16 \rule[-1ex]{0pt}{0pt}& 80 \\
    \hline \rule{0pt}{2.5ex}20 \rule[-1ex]{0pt}{0pt}& 65 \\
    \hline \rule{0pt}{2.5ex}24 \rule[-1ex]{0pt}{0pt}& 60 \\
    \hline \rule{0pt}{2.5ex}28 \rule[-1ex]{0pt}{0pt}& 65 \\
    \hline \rule{0pt}{2.5ex}32 \rule[-1ex]{0pt}{0pt}& 75 \\
    \hline \rule{0pt}{2.5ex}36 \rule[-1ex]{0pt}{0pt}& 65 \\
    \hline \rule{0pt}{2.5ex}40 \rule[-1ex]{0pt}{0pt}& 35 \\
    \hline
    \end{array}
      
    Use the information provided to graph the levels of hCG in a normal pregnancy.   (3 marks)
     
  2. Describe the role and changes in levels of a hormone in pregnancy.   (3 marks)

Show Answers Only

a.   

b.   The role and changes in levels of hormones in pregnancy.

→ Progesterone is a sex hormone which is initially secreted by the corpus leuteum after ovulation to thicken the endometrium for implantation.

→ Once the placenta has developed, it then increases the progesterone levels which maintain the pregnancy.

→ Progesterone levels eventually drop in the last stage of pregnancy to facilitate delivery.
  

Answers could also include information about other hormones including

→ Oestrogen

→ hCG

Show Worked Solution

a.   

b.   The role and changes in levels of hormones in pregnancy.

→ Progesterone is a sex hormone which is initially secreted by the corpus leuteum after ovulation to thicken the endometrium for implantation.

→ Once the placenta has developed, it then increases the progesterone levels which maintain the pregnancy.

→ Progesterone levels eventually drop in the last stage of pregnancy to facilitate delivery.
  

Answers could also include information about other hormones including

→ Oestrogen

→ hCG

BIOLOGY, M5 EQ-Bank 2 MC

A student completed a genetics exercise by preparing a Punnett square. `T` represents a dominant allele and `t` represents a recessive allele.
 

What were the likely genotypes of these parents?

  1. Both parents were homozygous.
  2. Both parents were heterozygous.
  3. Parent 1 was homozygous, Parent 2 was heterozygous.
  4. Parent 1 was heterozygous, Parent 2 was homozygous.
Show Answers Only

`B`

Show Worked Solution

→ Genotype ratio `1:2:1` is a typical Mendelian ratio of a cross between 2 heterozygous parents.

`=>B`

BIOLOGY, M5 EQ-Bank 4 MC

A student constructed a model of meiosis as shown. However, there is an error in the model.
 

Which aspect of this model does NOT fit with observations of meiosis?

  1. Separation of chromatids has not been shown in the model.
  2. The chromosomes have not independently assorted in stage 2 .
  3. The chromosomes in stage 4 should have duplicated before stage 5 .
  4. The chromosomes have undergone crossing over before sister chromosome alignment in stage 3 .
Show Answers Only

`D`

Show Worked Solution

→ Stage 4 and 5 have to switch to fix the error. All other aspects are correct.

`=>D`

PHYSICS, M8 EQ-Bank 22

Einstein's equation `E = mc^(2)`  is one of the most important equations in the history of physics.

Justify this statement.   (7 marks)

Show Answers Only

`E=mc^(2)` at its most basic level, expresses the concept that mass and energy are interchangeable.

Its importance is due to its critical role in explaining and analysing a broad range of ideas, processes and phenomena. These include:

→  The energy sourced from the processes of nuclear fission and fusion, including the energy associated with radioactive decay.

→ The relationship between the binding energy of atoms and their mass defect.

→ Mass dilation of objects approaching the speed of light.

→ The fundamental principles and technology upon which nuclear bombs and nuclear reactors operate.

→ Processes which source energy in stars through the conversion of mass into energy.

→ Processes which allow for particle accelerators to operate, allowing us to investigate into the fundamental structure and properties of matter.

Other equations, such as Newton’s Universal Law of Gravity, do not have the same myriad of applications in fields that make up our current understanding of physics.

It is therefore justified in being called one of the most important equations in the history of physics

Show Worked Solution

`E=mc^(2)` at its most basic level, expresses the concept that mass and energy are interchangeable.

Its importance is due to its critical role in explaining and analysing a broad range of ideas, processes and phenomena. These include:

→  The energy sourced from the processes of nuclear fission and fusion, including the energy associated with radioactive decay.

→ The relationship between the binding energy of atoms and their mass defect.

→ Mass dilation of objects approaching the speed of light.

→ The fundamental principles and technology upon which nuclear bombs and nuclear reactors operate.

→ Processes which source energy in stars through the conversion of mass into energy.

→ Processes which allow for particle accelerators to operate, allowing us to investigate into the fundamental structure and properties of matter.

Other equations, such as Newton’s Universal Law of Gravity, do not have the same myriad of applications in fields that make up our current understanding of physics.

It is therefore justified in being called one of the most important equations in the history of physics

PHYSICS, M8 EQ-Bank 3 MC

A 5-gram sample of radioactive strontium-90 decayed over time. The graph shows the mass of strontium-90 remaining from the initial sample as a function of time.
 

What is the approximate value of the decay constant, in `\text{year}^(-1)`, for strontium-90?

  1. 0.006
  2. 0.011
  3. 0.014
  4. 0.025
Show Answers Only

`D`

Show Worked Solution

→ From the graph, the half life (mass = 2.5 g) is approximately 29 years.

`lambda` `=(ln2)/(t_((1)/(2)))`  
  `=(ln2)/(29)`  
  `=0.0239\ text{year}^(-1)`  

 
`=>D`

PHYSICS, M8 EQ-Bank 4 MC

Which of the following is true in relation to Millikan's oil drop experiment?
 

Show Answers Only

`D`

Show Worked Solution

→ Millikan’s experiment involved levitating oil drops in an electric field in order to measure the charge on an electron.

`=>D`

PHYSICS, M8 EQ-Bank 2 MC

After DC voltage was applied to an apparatus containing hydrogen gas, the hydrogen separated into streams of oppositely charged particles.

What could be concluded from this observation?

  1. Hydrogen gas conducts electricity.
  2. Hydrogen is the simplest element.
  3. Hydrogen atoms have components.
  4. Hydrogen atoms have a neutral charge.
Show Answers Only

`C`

Show Worked Solution

→ The separation shows that hydrogen atoms contain both positive (protons) and negative (electrons) components.

`=>C`

PHYSICS, M8 EQ-Bank 1 MC

A Hertzsprung-Russell diagram is shown.
 

In which region would a star have the same surface temperature as a star on the main sequence?

  1. `P`
  2. `Q`
  3. `R`
  4. `S`
Show Answers Only

`D`

Show Worked Solution

→ Using the `x`-axis of the Hertzsprung-Russel diagram, `S` is the only region in which stars have the same surface temperature as a star on the main sequence.

`=>D`