Question

It is essential to consider light as a stream of photons to explain?
A- diffraction of light
B- Refraction of light
C- photoelectric effect
D- Reflection of light

Answer 1

Light possesses dual nature, particle nature and wave nature. Some phenomena of light can be explained by considering the particle nature while others by considering the wave nature.

Complete step by step answer: Refraction of light is a phenomenon in which light travels from one medium to another. In refraction, there is bending of light which takes place. While considering the refraction light behaves as a wave.
In reflection there is bouncing back of light into the same medium. In case of reflection there is no change in speed of light. Also, while considering the reflection of light, light behaves as a wave.
Diffraction of light, is a phenomenon of light bending along the edges of obstacles provided that the size of the obstacle is comparable to the size of the wavelength of the light. Again, in this picture, light behaves as a wave.
In photoelectric effect, each photon is absorbed by the electrons and when the energy of the electrons becomes greater than the work function of the metal, electrons get emitted. This can be explained only when light is considered as a particle.

So, the correct option is (c)

Note: There exists a frequency called threshold frequency below which no photo electric effect can take place. Threshold frequency is a characteristic of the material. Most metals show photoelectric effect.