If the frequency of incident radiation $(v)$ is increased,keeping other factors constant,the stopping potential ($v > v_0$,threshold frequency) will:

The threshold wavelength for the photoelectric effect on sodium is $5000 \ Å$. Its work function is:

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$ : The photoelectric effect does not take place,if the energy of the incident radiation is less than the work function of a metal.
Reason $R$ : Kinetic energy of the photoelectrons is zero,if the energy of the incident radiation is equal to the work function of a metal.
In the light of the above statements,choose the most appropriate answer from the options given below.

The work function of a surface of a photosensitive material is $6.2\, eV$. The wavelength of the incident radiation for which the stopping potential is $5\, V$ lies in the

When a photosensitive surface is irradiated by light of wavelengths $\lambda_1$ and $\lambda_2$,the kinetic energies of the emitted photoelectrons are $E_1$ and $E_2$ respectively. The work function of the photosensitive surface is:

If in a photoelectric experiment,the wavelength of incident radiation is reduced from $6000 \, \mathring{A}$ to $4000 \, \mathring{A}$,then: