Physics, asked by narmeenbeeda3944, 11 months ago

A point source of light is placed at a distance d from the photo cell.if the distance becomes d/3 then number of electrons per second

Answers

Answered by Fatimakincsem
2

Therefore, Number of electrons emitted is a quarter of the initial number.

Explanation:

Intensity, I =  E /At

  • E = the total energy of source,
  • A = area of illuminated surface,
  • t = time

I = E /  4πr^2  t  

I1 / I2 = E /  4πr1^2 t  x  4πr2^2  t  / E

I1 / I2 = r2^2 / r1^2

I1 / I2  = 4 / 1

I2 / I1 = 1 / 4

Since, ∝ number of photo-electrons emitted

Therefore, Number of electrons emitted is a quarter of the initial number.

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