Based upon Max Planck's theory of black-body radiation, Einstein theorized that the energy in each quantum of light was equal to the frequency multiplied by a constant, later called Planck's constant. A photon above a threshold frequency has the required energy to eject a single electron, creating the observed effect.
According to Max Planck light energy is quantized and is released or absorbed as an integer multiple of a small packet of energy which he called a photon. Therefore the energy stored in a photon of light is given by the equation,
E = hV
where E is the energy of the photon, v is the frequency of light and h is the Planck’s constant.
Einstein used the concept of light behaves as photons, discrete energy packets instead of waves to explain the photoelectric effect.
The slight positive charges on the hydrogen atoms in water molecules attract the slight negative charges on the oxygen atoms of the other water molecules
When heat flows from one object or substance to another it is in contact with, the objects or substances are said to be in thermal contact. The state where objects in thermal contact with each other reach the same temperature, no heat flows between them.
