2.2 eV

2.7 eV

1.9 eV

7 eV

$m C^2$

$v \lambda$

$\frac{h v}{\mathrm{mC}}$

$\frac{C^2}{v}$

$4: 3$

$9: 16$

$3: 4$

$16: 9$

The electrons are ejected from the metal surface as soon as the beam of light strikes to the surface.

The number of electrons ejected is proportional to the intensity or brightness of light.

There is a time lag between the striking of light beam and the ejection of electrons from the metal surface.

For each metal, there is a characteristic minimum frequency below which photoelectric is not observed.