Which of the following provides evidence for the model of light proposed by Huygens?
- Emission spectra
- Diffraction of light
- Black body radiation
- The photoelectric effect
PHYSICS M7 2022 HSC 27
A laser producing red light of wavelength 655 nm is directed onto double slits separated by a distance, `d=5.0 xx 10^{-5} \ text{m}`. A screen is placed behind the double slits.
- Newton proposed a model of light. Use a labelled sketch to show the pattern on the screen that would be expected from Newton's proposed model. (2 marks)
- When the laser light is turned on, a series of vertical bright lines are seen on the screen.
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- Calculate the angle, `\theta`, between the centre line and the bright line at `A`. (3 marks)
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- The laser is replaced with one producing green light of wavelength 520 nm.
- Explain the difference in the pattern that would be produced. (2 marks)
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Show Answers Only
a.
b. `theta=1.50^@`
c. Consider `d sin theta = m lambda :`
- `sin theta prop lambda`
- Using light with a shorter wavelength decreases the angular separation of bright fringes.
- The bright lines will appear closer together.
Show Worked Solution
a.
Mean mark part (a) 53%.
b. Using `d sin theta=mlambda:`
| `5.0 xx10^(-5) sin theta` | `=2 xx6.55xx10^(-7)` |
| `sin theta` | `=(2 xx6.55xx10^(-7))/(5.0 xx10^(-5))` |
| `theta` | `=1.50^@` |
c. Consider `d sin theta = m lambda :`
- `sin theta prop lambda`
- Using light with a shorter wavelength decreases the angular separation of bright fringes.
- The bright lines will appear closer together.
PHYSICS, M7 2020 HSC 1 MC
The diagram shows a model used to explain the refraction of light passing from medium `X` into medium `Y`.
Who proposed this model?
- Malus
- Planck
- Newton
- Huygens