Let $v$ be the frequency of the incident photon and $v_0$ be the threshold frequency. The condition for the emission of photoelectrons is:

Two identical photo-cathodes receive light of frequencies $f_1$ and $f_2$. If the velocities of the photoelectrons (of mass $m$) coming out are respectively $v_1$ and $v_2$,then:

If the wavelength of incident light is decreased from $4000 \ \mathring{A}$ to $3600 \ \mathring{A}$,then the change in stopping potential will be ............. $V$.

Two photons of energies twice and thrice the work function of a metal are incident on the metal surface. Then,the ratio of maximum velocities of the photoelectrons emitted in the two cases respectively,is

Sodium and copper have work functions of $2.3 \ eV$ and $4.5 \ eV$ respectively. The ratio of their threshold wavelengths is approximately .......

Why can wave theory not explain the change in the kinetic energy of an electron with a change in the frequency of incident light?