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. $π$

Lead is not used in calorimeter because

1. it has high specific heat
2. it is not a metal
3. it is a toxic metal
4. it is not a solid metal

If refractive index of glass w.r.t. air is $\dfrac{3}{2}$. What is the refractive index of air w.r.t. glass?

1. $\dfrac{3}{4}$

2. $\dfrac{4}{3}$

3. $\dfrac{3}{2}$

4. $\dfrac{2}{3}$