How does the width W of the central maximum formed from diffraction th...
Width of central maxima is inversely proportional to slit width or aperture size .
The correct answer is: W decreases as b increases
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How does the width W of the central maximum formed from diffraction th...
The width of the central maximum formed from diffraction through a circular aperture (pupil) depends on the size of the aperture. Let's explore how the width (W) changes with the aperture size (b) for a fixed distance away from the aperture.
Explanation:
The width of the central maximum can be determined using the equation:
W = (2λL) / b
where W is the width of the central maximum, λ is the wavelength of light, L is the distance between the aperture and the screen, and b is the size of the aperture.
If we consider a fixed distance L, we can analyze how W changes as b increases.
1. When b is small:
If the aperture size (b) is small compared to the wavelength of light (λ), the width of the central maximum (W) will be relatively large. This is because the diffraction effects will be more significant, causing the light to spread out more.
2. When b is large:
If the aperture size (b) is large compared to the wavelength of light (λ), the width of the central maximum (W) will be relatively small. This is because the diffraction effects will be less significant, causing the light to spread out less.
Therefore, as the aperture size (b) increases, the width of the central maximum (W) decreases. This is because larger apertures allow more light to pass through without significant diffraction, resulting in a narrower central maximum.
Hence, the correct answer is option 'A': W decreases as b increases.