Question

Shining light of wavelength $\lambda$ and intensity $I$ is incident on a surface $S$ produces photoelectrons at a rate $R$ with maximum kinetic energy $E$. Consider the following statements from the effect of changing one parameter at a time
Doubling $I$ always doubles $R$
Doubling $I$ does not change $E$ at all
Making $\lambda$ half always makes $E$ more than double

• A. $!$ and $2$ only
• B. $2$ and $3$ only
• C. $1$ and $3$ only
• D. all the above

Answer 1

The correct option is D all the above

Doubling $I$ means doubling the number of photon falling over unit area.

Electron will absorb single photon, so doubling intensity will double the rate of emission of photo electron but will not cause change in KE.

Changing wave length by half will double the energy energy of photon, hence will double the Kinetic energy.