Q1. In a thin film of oil on water, which color will appear at the center of the pattern if the film thickness is such that it causes constructive interference for red light? (2022)
Solution:
The color that appears at the center of the pattern corresponds to the wavelength that experiences constructive interference, which in this case is red light.
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Q2. In thin film interference, which of the following will cause a shift in the interference pattern? (2022)
Solution:
All these factors can affect the path difference and thus shift the interference pattern in thin film interference.
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Q3. In a diffraction pattern, the central maximum is observed to be the brightest. What is the reason for this? (2022)
Solution:
The central maximum has the maximum intensity because all light waves arrive in phase at this point, leading to constructive interference.
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Q4. In a thin film of oil on water, which color will appear at the center of the pattern if the film is viewed in white light? (2022)
Solution:
At the center of the thin film interference pattern, the color that appears is typically green due to the constructive interference of wavelengths in that range.
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Q5. A beam of light passes through a narrow slit and produces a diffraction pattern. What is the angle of the first minimum? (2019)
Solution:
The angle of the first minimum in single-slit diffraction is given by sin(θ) = λ/a, where a is the width of the slit.
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Q6. What is the relationship between the wavelength of light and the angle of diffraction in a single-slit experiment? (2023)
Solution:
The angle of diffraction is inversely proportional to the wavelength; as the wavelength increases, the angle of diffraction decreases.
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Q7. In a thin film of oil on water, which color will appear at the center of the pattern if the film thickness is such that it causes constructive interference for blue light? (2022)
Solution:
If the film thickness causes constructive interference for blue light, blue will appear at the center of the pattern.
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Q8. A thin film of oil (n = 1.5) is on water (n = 1.33). What is the condition for destructive interference for light of wavelength 600 nm in air? (2022)
Solution:
For destructive interference in a thin film with a higher refractive index below, the condition is 2t = (m + 1/2)λ/n, where n is the refractive index of the film.
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Q9. A beam of light passes through a narrow slit and produces a diffraction pattern. What happens to the width of the central maximum if the slit width is decreased? (2019)
Solution:
According to the diffraction principle, as the slit width decreases, the width of the central maximum increases.
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Q10. What is the effect of increasing the slit width in a single-slit diffraction experiment? (2021)
Solution:
Increasing the slit width decreases the fringe width because the angle of diffraction decreases.
