The value of the stopping potential in the following diagram is ......... $V$.

The distance between a light source and a photoelectric cell is $d$. If the distance is decreased to $\frac{d}{2}$,then:

The number of photo-electrons emitted per second from a metal surface increases when:

What is the phenomenon of the photoelectric effect?

$A$ caesium photocell,with a steady potential difference of $60 \ V$ across it,is illuminated by a bright point source of light $50 \ cm$ away. When the same light source is placed $1 \ m$ away,the photoelectrons emitted from the cell:

Light of wavelength $4000 Å$ is incident on a sodium surface for which the threshold wavelength of photoelectrons is $5420 Å$. The work function of sodium is (in $eV$)