Question

The photoelectric effect can be explained on the basis of:
A. Corpuscular theory of light
B. Wave theory of light
C. Electromagnetic theory of light
D. Quantum theory of light

Answer 1

Hint:Photoelectric effect is the process in which, when an electromagnetic wave such as a light is incident on a metal surface, then the electrons in the metal get excited and a current can be seen flowing through a battery as the electrons possess kinetic energy and hence start moving from one end of the battery to the other.

Complete answer:
Photoelectric effect is a phenomenon in which, when light is incident on a metal surface, then electrons are ejected from the surface. Now, light is an electromagnetic wave and is not made up of particles. But, the same light collides with the electrons, which are particles, and because of their collision, electrons get excited and through that, they travel outside of the metal through kinetic energy.

This is because light is not only of particle nature, but it also has wave nature, that is they have wave particle duality. Light, which is made up of imaginary particles which are photons, they transmit energy in the form of quanta. Quanta are packets of energy, and the energy here is due to the fact that light is a wave, while the photon collides with electrons showing the particle nature. The energy of the photons is given as follows:
\[E = nhf\]
Here, $E$ is the total energy of the light wave, $f$ is the wave’s frequency, $h$ is the Planck’s constant and $n$ is a natural number. This is the quantum theory of light.

Hence option D is the correct answer.

Note:The phenomenon is seen on metal surfaces because metals possess free electrons in them, which are very loosely bound and can roam around inside the metal surface. Thus these weakly bound electrons get excited and produce current. The minimum energy of light is required to obtain the photoelectric effect, which is called threshold energy.