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Light of wavelength \lambda shines on a metal emits y electrons per second of average energy z. What will happen to y and z if Intensity of light is doubled?

Option: 1

Y will be doubled and z will be half


Option: 2

y will remain same and z will be doubled


Option: 3

Both y and z will be doubled


Option: 4

y will be doubled but z will remain same.


Answers (1)

best_answer

Photoelectric Effect -

The electrons are ejected from the metal surface as soon as the beam of light of a particular frequency strikes the surface.

Formula:

\frac{1}{2}mu^{2}= hv-hv_{0}

where

m is the mass of the electron

u is the velocity associated with the ejected electron.

h is plank’s constant.

v is frequency of photon,

v0 is threshold frequency of metal.

As we have learnt,

The number of electrons ejected from the metal surface is proportional to the intensity of light. Thus if intensity is doubled, then the number of ejected electrons will also be doubled.
The energy of electrons only depends upon the wavelength of light. Thus if wavelength is not changing, then energy will remain same.

Therefore, Option(4) is correct.

Posted by

vinayak

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