When a metal surface is illuminated with light of wavelength $\lambda$,the stopping potential is $V$. When the same surface is illuminated by light of wavelength $2\lambda$,the stopping potential is $V/3$. The threshold wavelength for the surface is:

In the experiment of $P.E.E.$ (Photoelectric Effect), the saturation current is $5\,mA$ and the stopping potential is $10\,V$. If the intensity and frequency of the incident light are both doubled, then what will be the new saturation current $(i_s)$ and stopping potential $(V_s)$?

$A$ copper ball of radius $1\, cm$ and work function $4.47\, eV$ is irradiated with ultraviolet radiation of wavelength $2500\, \mathring{A}$. The effect of irradiation results in the emission of electrons from the ball. Further,the ball will acquire charge,and due to this,there will be a finite value of the potential on the ball. The charge acquired by the ball is:

The threshold wavelength for the photoelectric effect on sodium is $5000\;\mathring{A}$. Its work function is:

In a photoelectric experiment,a graph is drawn with stopping potential along $Y$-axis and the frequency of the incident light along $X$-axis. If the graph is a straight line which makes an angle $\theta$ with $Y$-axis,then $\tan \theta=$ ($h$-Planck's constant,$e$-charge of electron).

Light of frequency $\nu$ is incident on a substance of threshold frequency $\nu_0$ (where $\nu_0 < \nu$). The maximum kinetic energy of the emitted photo-electron will be: