AIPMT PRELIMS2007Physics-Photoelectric Effect
AIPMT PRELIMS 2007 Physics Intensity and Distance MCQ Question
Type: MCQ-conceptual-Medium-Class 12
A 5 watt source emits monochromatic light of wavelength 5000 Å. When placed 0.5 m away, it liberates photoelectrons from a photosensitive metallic surface. When the source is moved to a distance of 1.0 m, the number of photoelectrons liberated will be reduced by a factor of
A
8
B
16
C
2
D
4
Correct Answer
Option D
Detailed Explanation
The intensity of light decreases with the square of the distance. Doubling the distance reduces the intensity by a factor of 4, thus reducing the number of photoelectrons by the same factor.
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