During refraction __________ will not change.
A-Wavelength
B-Frequency
C-speed of light
D-none of the above

Hint: 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 and due to that bending one of the characteristics of the travelling wave/light changes.

Complete step by step answer:
In refraction of light, there always takes place bending of light. The bending of light takes place around normal. If light travels from one medium to another medium, then there is a change in wavelength of light. Also, we need to keep in mind that frequency is the characteristic of the source. It does not matter whether there is a change of medium or there is a change in the speed of light, but the frequency always remains the same. Also frequency, wavelength and speed of light are related to one another by the condition, Speed= frequency times wavelength. Since there is a change in wavelength and frequency does not change so speed also changes. Hence the correct option is (B).

Additional information:
In reflection of light, there is bouncing back of light into the same medium.Since the light travels in the same medium its speed does not change but in the case of refraction, there is a change of medium and hence such speed changes. Also if the wave is an electromagnetic wave then its speed will not change as it travels with a constant speed. Light is also an electromagnetic wave and it falls in the visible spectrum of the electromagnetic spectrum.

Note:Refraction is sometimes confused with reflection but in reality, both are quite different. In reflection there is bouncing back of light into the same medium, and hence speed does not change while in case of refraction speed of light changes on account of change of medium.