Need
the principle of the photoelectric effect is:

the principle of superposition
the electromagnetic theory of light
the special theory of relativity
the quantum theory of radiation

A

Explanation:

Photoelectric effect :

When a light hits a metal then the electrons emits from the metal surface and  this process is called photoelectric effect. The emitted electrons are called photo-electrons.

According to this process, we conclude that some electrons were emitted by the zinc plate when exposed to ultraviolet light.

Electromagnetic theory of light :

The particles oscillate in perpendicular to the direction of travel of the wave motion.

Light is a electromagnetic wave that can be seen by the human eyes.

All electromagnetic waves can travel through a vacuum.

Hence,  The electromagnetic theory of light.

at right angles to each other

energy stored in the capacitor= 9.72 x 10⁻⁴ j

explanation:

the energy stored in the capacitor is given by

e= 1/2 c v²

e= energy stored

c= capacitance= 1.5 µc= 1.5 x 10⁻⁶f

v= potential difference=36 v

so energy stored= e= 1/2 (1.5 x 10⁻⁶) (36)²

energy stored= 9.72 x 10⁻⁴j