MCQ

Share

A photocell is illuminated by a small bright source placed $1\ m$ away. When the same source of light is placed $\frac 12m$ away, the number of electrons emitted by photo cathode would

• A
  Decrease by a factor of $2$
• B
  Increase by a factor of $2$
• C
  Decrease by a factor of $4$
• ✓
  Increase by a factor of $4$