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 ........... $eV$.

With reference to the observations in photoelectric effect,identify the correct statements from below:
$A.$ The square of maximum velocity of photoelectrons varies linearly with frequency of incident light.
$B.$ The value of saturation current increases on moving the source of light away from the metal surface.
$C.$ The maximum kinetic energy of photoelectrons decreases on decreasing the power of $LED$ (light emitting diode) source of light.
$D.$ The immediate emission of photoelectrons out of metal surface can not be explained by particle nature of light/electromagnetic waves.
$E.$ Existence of threshold wavelength can not be explained by wave nature of light/electromagnetic waves.
Choose the correct answer from the options given below:

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

When photons of energies twice and thrice the work function of a metal are incident on the metal surface one after other,the maximum velocities of the photoelectrons emitted in the two cases are $V_1$ and $V_2$ respectively. The ratio $V_1: V_2$ is

The work function of caesium is $2.14\, eV$. Find the wavelength of the incident light if the photo current is brought to zero by a stopping potential of $0.60\, V$. (Result in $nm$)

When light of frequency twice the threshold frequency is incident on a metal plate,the maximum velocity of the emitted electron is $v_{1}$. When the frequency of incident radiation is increased to five times the threshold value,the maximum velocity of the emitted electron becomes $v_{2}$. If $v_{2} = x v_{1}$,the value of $x$ will be...........