When a metallic surface is illuminated with radiation of wavelength $\lambda$,the stopping potential is $V$. If the same surface is illuminated with radiation of wavelength $3 \lambda$,the stopping potential is $V/4$. The threshold wavelength for the metallic surface is.

Light of wavelength $488 \, nm$ produced by an Argon laser is used in the photoelectric effect. When light from this spectral line is incident on the cathode, the stopping potential of the photoelectrons is $0.38 \, V$. The work function of the cathode material is (in $ \, eV$)

The work function of caesium is $2.14 \ eV$. Find the wavelength of the incident light if the photocurrent is brought to zero by a stopping potential of $0.60 \ V$.

When light of a given wavelength is incident on a metallic surface,the minimum potential needed to stop the emitted photoelectrons is $6.0 \ V$. This potential drops to $0.6 \ V$ if another source with wavelength four times that of the first one and intensity half of the first one is used. What are the wavelength of the first source and the work function of the metal,respectively? $\left[\text{Take } hc = 1.24 \times 10^{-6} \ J \ m\right]$

Photons of energy $6 eV$ are incident on a metal surface whose work function is $4 eV$. The minimum kinetic energy of the emitted photo-electrons will be ........... $eV$.

The work function of caesium is $2.14 \ eV$. Find
$(a)$ the threshold frequency for caesium,and
$(b)$ the wavelength of the incident light if the photocurrent is brought to zero by a stopping potential of $0.60 \ V$.