The graph that depicts Einstein's photoelectric effect for a monochromatic source of frequency above the threshold frequency is

The total energy of an atomic electron is :

Which of the following is $NOT$ observed in Rutherford's alpha-particle scattering experiment?

If $\lambda_0$ and $\lambda$ are respectively the threshold wavelength and wavelength of incident light,the velocity of photoelectrons ejected from the metal surface is

What will be the number of photons required to obtain $1 \ J$ of energy by radiation having a wavelength of $4000 \ \mathring{A}$?

In a $He^{+}$ ion,an electronic transition occurs from orbit $n_2$ to $n_1$ such that:
$2n_2 + 3n_1 = 18$
$2n_2 - 3n_1 = 6$
What is the total number of photons emitted when the electron transitions to the $n_1$ orbit?