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Figure 3 shows an arrangement to investigate diffraction - AQA - A-Level Physics - Question 3 - 2019 - Paper 1
Question 3
Figure 3 shows an arrangement to investigate diffraction. White light is incident on a single slit. After leaving the slit, the diffracted light passes through a gre... show full transcript
Worked Solution & Example Answer:Figure 3 shows an arrangement to investigate diffraction - AQA - A-Level Physics - Question 3 - 2019 - Paper 1
Step 1
Describe the pattern produced on the screen.
Answer
The pattern produced on the screen consists of a central maximum with lower intensity maxima on either side. The central maximum is wider than the other maxima. This can be attributed to the diffraction of light passing through the single slit.
Step 2
Describe the change in the pattern produced on the screen.
Answer
When the green filter is replaced with a red filter, the pattern remains similar, but the intensity of all maxima may decrease. The red light will produce a central maximum that is also wider, but now the color would appear red, aligning with the characteristic of red light.
Step 3
Calculate the angle θ between a first-order maximum and the central maximum.
Answer
To find the angle θ, we use the diffraction equation:
Given:
- Wavelength = 650 nm = 650 x 10^{-9} m
- Grating lines = 500 lines/mm = 500 x 10^{3} lines/m
- d = 1 / 500 x 10^{3} = 2 imes 10^{-6} m
For first-order maximum (m = 1), we have:
Thus, θ = sin^{-1}(0.325) ≈ 19.0 degrees.
Step 4
Suggest how this affects the appearance of the maxima.
Answer
The range of wavelengths in the 600 nm to 700 nm range results in a broader central maximum compared to when only a single wavelength is used. As the wavelengths vary, different colors will overlap, leading to less distinct maxima. This results in a more blended and potentially less sharp appearance of the output light on the screen.