Question

When light is incident on a surface, photoelectrons are emitted.

For those photoelectrons:

• A. The value of kinetic energy is same
• B. Kinetic energy does not depend on the wave length of incident light
• C. The value of kinetic energy is equal to or less than a maximum energy
• D. None of the above

Answer 1

The correct option is B Kinetic energy does not depend on the wave length of incident light

Kinetic energy of photo electron is

$KE=h\nu -W=\frac{hc}{\lambda }-Wh=plancksconstant\nu =frequency\lambda =wavelengthofincidentlightW=workforce$

The photo electrons are not emitted instantly. They collide several times with other electrons within the metal before coming out. Hence the value of kinetic energy is not the same. From above equation, Kinetic energy depends on wavelength of incident light.Also the value of kinetic energy is less than or equal to $h\nu$