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.

a high pressure system is a dense air mass that is usually cooler and drier than the surrounding air. a low pressure system is a less dense air mass that is usually wetter and warmer than the surrounding air.

in general, areas that experience high atmospheric pressure also experience fair weather. low pressure systems can cause the formation of clouds and storms. air usually flows from areas of high pressure to areas of low pressure..