The following graph, based on the data gathered by Hubble, shows the relationship between the recessional velocity of galaxies and their distance from Earth. --- 4 WORK AREA LINES (style=lined) --- --- 6 WORK AREA LINES (style=lined) ---
PHYSICS, M7 2023 VCE 19*
The diagram below shows the spectrum of light emitted by a hydrogen vapour lamp. The spectral line indicated by the arrow on the diagram is in the visible region of the spectrum.
Calculate the frequency of the light corresponding to the spectral line indicated by the arrow. (2 marks)
--- 4 WORK AREA LINES (style=lined) ---
PHYSICS, M7 2019 HSC 2 MC
Two stars were observed from Earth. Their spectra are shown with the wavelength in nanometres.
Using these spectra, what can be concluded about the motion of the stars relative to Earth and their chemical compositions?
\begin{align*}
\begin{array}{l}
\rule{0pt}{2.5ex} \ \rule[-1ex]{0pt}{0pt}& \\
\rule{0pt}{2.5ex}\textbf{A.}\rule[-1ex]{0pt}{0pt}\\
\rule{0pt}{2.5ex}\textbf{B.}\rule[-1ex]{0pt}{0pt}\\
\rule{0pt}{2.5ex}\textbf{C.}\rule[-1ex]{0pt}{0pt}\\
\rule{0pt}{2.5ex}\textbf{D.}\rule[-1ex]{0pt}{0pt}\\
\end{array}
\begin{array}{|c|c|}
\hline
\rule{0pt}{1.5ex}\textit{Motion relative to Earth}\rule[-0.5ex]{0pt}{0pt}& \textit{Chemical composition} \\
\hline
\rule{0pt}{2.5ex}\text{The same}\rule[-1ex]{0pt}{0pt}&\text{The same}\\
\hline
\rule{0pt}{2.5ex}\text{Different}\rule[-1ex]{0pt}{0pt}& \text{The same}\\
\hline
\rule{0pt}{2.5ex}\text{The same}\rule[-1ex]{0pt}{0pt}& \text{Different} \\
\hline
\rule{0pt}{2.5ex}\text{Different}\rule[-1ex]{0pt}{0pt}& \text{Different} \\
\hline
\end{array}
\end{align*}
PHYSICS, M7 2020 HSC 26
- Describe the difference between the spectra of the light produced by a gas discharge tube and by an incandescent lamp. (2 marks)
--- 4 WORK AREA LINES (style=lined) ---
- The graph shows the curves predicted by two different models, `X` and `Y`, for the electromagnetic radiation emitted by an object at a temperature of 5000 K.
Identify an assumption of EACH model which determines the shape of its curve. (2 marks)
--- 4 WORK AREA LINES (style=lined) ---
- The diagram shows the radiation curve for a black body radiator at a temperature of 5000 K.
On the same diagram, sketch a curve for a black body radiator at a temperature of 4000 K and explain the differences between the curves. (4 marks)
--- 6 WORK AREA LINES (style=lined) ---
Show Answers Only
a. The spectra of light produced by a gas discharge tube will consist of lines only at a few discrete wavelengths.
The spectra of light produced by an incandescent lamp will be a continuous spectrum.
b. Model `X` black bodies absorb and emit energy continuously.
Model `Y` assumes that black bodies absorb and emit energy in discrete quantities.
c.
- Using `lambda_(max)=(b)/(T)\ \ =>\ \ lambda prop (1)/(T)`
- Therefore, the 4000 K curve will have a peak wavelength greater than the 5000 K curve.
- The area under the curve and the intensity at all wavelengths will be less for the 4000 K curve, as the total power output of a black body decreases as its temperature decreases.
Show Worked Solution
a. Differences:
- The spectra of light produced by a gas discharge tube will consist of lines only at a few discrete wavelengths.
- The spectra of light produced by an incandescent lamp will be a continuous spectrum.
♦ Mean mark (a) 39%.
b. Assumptions of EACH model:
- Model `X` black bodies absorb and emit energy continuously.
- Model `Y` assumes that black bodies absorb and emit energy in discrete quantities.
♦ Mean mark (b) 44%.
c.
- Using `lambda_(max)=(b)/(T)\ \ =>\ \ lambda prop (1)/(T)`
- Therefore, the 4000 K curve will have a peak wavelength greater than the 5000 K curve.
- The area under the curve and the intensity at all wavelengths will be less for the 4000 K curve, as the total power output of a black body decreases as its temperature decreases.
PHYSICS, M7 2021 HSC 5 MC
The spectrum of an object is shown.
Which row of the table correctly identifies the most likely source of the spectrum and the features labelled \(Y\)?
\begin{align*}
\begin{array}{l}
\rule{0pt}{1.5ex} \ \rule[-0.5ex]{0pt}{0pt}& \\
\rule{0pt}{2.5ex}\textbf{A.}\rule[-1ex]{0pt}{0pt}\\
\rule{0pt}{2.5ex}\textbf{B.}\rule[-1ex]{0pt}{0pt}\\
\rule{0pt}{2.5ex}\textbf{C.}\rule[-1ex]{0pt}{0pt}\\
\rule{0pt}{2.5ex}\textbf{D.}\rule[-1ex]{0pt}{0pt}\\
\end{array}
\begin{array}{|l|l|}
\hline
\rule{0pt}{1.5ex}\text{Source of spectrum}\rule[-0.5ex]{0pt}{0pt}& \textit{Features labelled \(Y\)} \\
\hline
\rule{0pt}{2.5ex}\text{Star}\rule[-1ex]{0pt}{0pt}&\text{Absorption lines}\\
\hline
\rule{0pt}{2.5ex}\text{Discharge tube}\rule[-1ex]{0pt}{0pt}& \text{Absorption lines}\\
\hline
\rule{0pt}{2.5ex}\text{Star}\rule[-1ex]{0pt}{0pt}& \text{Emission lines} \\
\hline
\rule{0pt}{2.5ex}\text{Discharge tube}\rule[-1ex]{0pt}{0pt}& \text{Emission lines} \\
\hline
\end{array}
\end{align*}