When a photon of energy $6 \, eV$ is incident on a metal surface,the maximum kinetic energy of the emitted photoelectrons is $4 \, eV$. The value of the stopping potential is .......... $V$.

If the energy of a photon is $25\, eV$ and the work function of the material is $7\, eV$,then the value of the stopping potential is :-................. $V$

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:

When a point source of monochromatic light is at a distance of $0.2 \ m$ from a photoelectric cell,the stopping potential and saturation photocurrent are $0.6 \ V$ and $18 \ mA$ respectively. If the same source is placed $0.6 \ m$ away from the photoelectric cell,then:

The threshold frequency of potassium is $3 \times 10^{14} \ Hz$. The work function is ...... .

The work function of a metal is $1 \ eV$. If light of wavelength $3000 \ \mathring{A}$ is incident on the surface of this metal, the maximum velocity of the emitted photoelectrons is ........