Waves

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R In the light of the above statements, choose the correct answer from the options given below

1. Both A and R are true and R is the correct explanation of A
2. A is false but R is true
3. A is true but R is false
4. Both A and R are true but R is NOT the correct explanation of A

Answer

(3) A is true but R is false

Solution

Speed of sound in a medium: v = E (E = elastic modulus, = density).

Solids have far larger elastic moduli than gases, so sound travels faster in solids (e.g. about 5000 m s-1 in steel, about 343 m s-1 in air) A is true.

Gases are highly compressible, so their bulk modulus B = - p V/V is much smaller than that of solids R is false.

Answer: (3)