Photoelectrons from a metal do not come out with the same energy. The most appropriate explanation is:

$A$ small metal ball is suspended in a uniform electric field with the help of an insulated thread. If a high energy $X-$ray beam falls on the ball,then the ball

The electrons are emitted in the photoelectric effect from a metal surface:

In a photoelectric experiment,a parallel beam of monochromatic light with power of $200 \ W$ is incident on a perfectly absorbing cathode of work function $6.25 \ eV$. The frequency of light is just above the threshold frequency so that the photoelectrons are emitted with negligible kinetic energy. Assume that the photoelectron emission efficiency is $100 \%$. $A$ potential difference of $500 \ V$ is applied between the cathode and the anode. All the emitted electrons are incident normally on the anode and are absorbed. The anode experiences a force $F = n \times 10^{-4} \ N$ due to the impact of the electrons. The value of $n$ is. . . . .
Mass of the electron $m_e = 9 \times 10^{-31} \ kg$ and $1.0 \ eV = 1.6 \times 10^{-19} \ J$.

Threshold frequency of which of the following metals does not lie in the ultraviolet region (in the case of the photoelectric effect)?

The electromagnetic theory of light failed to explain: