The correct descending order of the electro magnetic waves according to their wavelengths is

1. UV-rays, γ-rays, microwaves, infrared
2. infrared, microwaves, UV-rays, γ-rays
3. γ-rays, UV rays, Infrared rays, microwaves
4. microwaves, infrared rays, UV rays, γ-rays

Absolute unit of work is

1. joule
2. erg
3. Both (a) and (b)
4. None of these

The frequency of a source is 20 kHz. The frequency of sound wave produced by it in water and air will be

1. same as that source
2. > 20 kHz
3. < 20 kHz
4. Depend upon velocity

A ray is made to fall on a prism. Maximum deviation it can suffer is

1. $\dfrac{π}{3}$

2. $\dfrac{π}{4}$

3. $\dfrac{π}{2}$

4. $π$