MHT CET2007PhysicsSemiconductors
A photoelectric cell is illuminated by a point source of light 1 ~m away. When the source is shifted to 2 ~m then
Options
- Aeach emitted electron carries half the initial energy
- Bnumber of electrons emitted is a quarter of the initial number
- Ceach emitted electron carries one quarter of the initial energy
- Dnumber of electrons emitted is half the initial number
Correct answer
B. number of electrons emitted is a quarter of the initial number
Step-by-step solution
Key Idea Number of photoelectrons emitted per second is directly proportional to intensity of light. Intensity of light source is I 1 d² When distance is doubled, intensity becomes one-fourth. As number of photoelectrons intensity, so number of photoelectrons is quarter of the initial number.