A light meter measures the intensity of the light falling on it. Theory suggests that this varies as the inverse square of the distance . Which graph of the results supports this theory?
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Official Solution
Correct Option: (1)
The intensity of light follows the inverse square law, which means the intensity is proportional to . The graph that best represents this is the one where intensity decreases as the square of the distance increases.
02
PYQ 2017
medium
physicsID: ipu-cet-
Two coherent point sources and vibrating in phase emit light of wavelength . The separation between them is . The light is collected on a screen placed at a distance from the slit as shown. The minimum distance, so that intensity at is equal to intensity at , is:
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Official Solution
Correct Option: (2)
The condition for maximum intensity occurs when the path difference between the two sources is an integer multiple of the wavelength . For the intensity to be the same at point as at point , the path difference between the two sources must be . The minimum distance between the sources and the point where the intensity is equal is found using the formula for constructive interference, where the condition is satisfied at a distance . Thus, the correct answer is (b).
