Answer:
4 decreasing energy of a closed system
It measures<span> the relative humidity in the atmosphere through the use of two thermometers. The first, a dry bulb thermometer, is used to </span>measure<span> the temperature by being exposed to the air. The second, a wet bulb thermometer,</span>measures<span> temperature by having the bulb dipped in a liquid.</span>

The photoelectric effect is a phenomenon in which electrons are ejected from the surface of a metal when light is incident on it. These ejected electrons are called photoelectrons. It is important to note that the emission of photoelectrons and the kinetic energy of the ejected photoelectrons is dependent on the frequency of the light that is incident on the metal’s surface.