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A 5 watt source emits monochromatic light of wavelength 5000 Å. When placed 0.5 m away, it liberates photo electrons from a photosensitive metallic surface. When the source is moved to a distance of 1.0 m, the number of photo electrons liberated will be reduced by a factor of
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- 8
- 16
- 2
- 4
Correct Option: D
Number of emitted electrons NE ∝ Intensity
| ∝ | (Distance)2 |
Therefore, as distance is doubled, NE decreases by (1/4) times.
