smc-3703-30-Types of Radiation

PHYSICS, M8 2022 VCE 3 MC

Particles emitted from a radioactive source travel through a magnetic field, \(B_{\text {in }}\), directed into the page, as shown schematically in the diagram below.

Three particles, \(\text{K, L}\) and \(\text{M}\), follow the paths indicated by the arrows.

Which of the following correctly identifies the charges on particles \(\text{K, L}\) and \(\text{M}\)?

	\( \textbf{K} \)	\( \textbf{L} \)	\( \textbf{M} \)
A.	positive	no charge	negative
B.	positive	negative	negative
C.	negative	no charge	positive
D.	no charge	no charge	no charge

Show Answers Only

\(A\)

Show Worked Solution

→ \(\text{L}\) must have no charge as it travels through the magnetic field with no deflection.

→ Using the right-hand rule, the force on a positive charge would be up the page, hence \(\text{K}\) must be the positive charge.

\(\Rightarrow A\)

PHYSICS, M8 2023 HSC 11 MC

The chart shows part of a nuclear decay series beginning with uranium.

Which option correctly identifies \(X\) and \(Y\) and the process by which each was produced?

\(X\)

\(Y\)

\({ }_{\ \ 90}^{234}\text{Th}\)

alpha decay

\({ }_{\ \ 91}^{234}\text{Pa}\)

beta decay

\({ }_{\ \ 90}^{234}\text{Th}\)

alpha decay

\({ }_{\ \ 91}^{234}\text{Pa}\)

alpha decay

\({ }_{\ \ 91}^{234}\text{Pa}\)

beta decay

\({ }_{\ \ 90}^{234}\text{Th}\)

beta decay

\({ }_{\ \ 91}^{234}\text{Pa}\)

beta decay

\({ }_{\ \ 90}^{234}\text{Th}\)

alpha decay

Show Answers Only

\(A\)

Show Worked Solution

→ During the decay process producing \(X\), the Atomic number decreases by 2 to 90 and the Mass number decreases by 4 to 234

→ Alpha decay producing \({ }_{\ \ 90}^{234}\text{Th}\)

→ During the decay process producing \(Y\), the Atomic number increases by 1 to 91 and the Mass number does not change.

→ Beta decay producing \({ }_{\ \ 91}^{234}\text{Pa}\)

\(\Rightarrow A\)

The graph shown plots isotopes in terms of their numbers of protons and neutrons. When an isotope undergoes nuclear decay, it will move to a different location on the graph. The movement can be represented with an arrow.

Which arrow would correctly describe beta negative `(beta^(-))` decay on the graph?

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`A`

Show Worked Solution

→ In `beta^(-)` decay, a neutron is converted into a proton and an electron.

→ The number of neutrons decreases by one and the number of protons increase by one.

→ This corresponds to a movement downwards and to the right on the graph.

`=>A`

PHYSICS M6 2022 HSC 3 MC

A radioisotope emits radiation which is deflected by an electric field, as shown.

What type of radiation is this?

Alpha
Gamma
Beta positive (positron)
Beta negative (electron)

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`D`

Show Worked Solution

The radiation experiences a force of attraction towards the positive plate.

→ it must be negatively charged.

`=>D`

PHYSICS, M8 2020 HSC 8 MC

A uranium isotope, `U`, undergoes four successive decays to produce `Q`.

Which row of the table correctly shows the decay process `R` and product `Q` ?

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`C`

Show Worked Solution

Decay process `R` reduces the number of both protons and neutrons by two → alpha decay.

Thorium has atomic number 90.

`=>C`

PHYSICS, M8 2021 HSC 19 MC

Rh-106 is a metallic, beta-emitting radioisotope with a half-life of 30 seconds.

A sample of Rh-106 and an electrode are placed inside an evacuated chamber. They are connected to a galvanometer and a variable DC power supply.

A student measures the current, `I`, when the power supply is set to zero. They then measure the stopping voltage, `V_s`. The stopping voltage is the minimum voltage needed to prevent current flowing.

A few minutes later, these measurements are repeated.

How do the TWO sets of measurements compare?

Only `I` changes.
Only `V_s` changes.
Both `I` and `V_s` change.
Neither `I` nor `V_s` changes.

Show Answers Only

`A`

Show Worked Solution

Due to the short half life of the isotope, there will be significantly less present when the second reading is made.

→ Lower rate of emission of electrons → Lower recorded current

The energy of emitted electrons will remain the same → Voltage will not change

`=>A`

♦ Mean mark 29%.