Question

Sound wave is travelling along positive x-direction Displacement (y) of particles at any time t is as shown in figure. Select the wrong statement:

(a) Particle located at E has its velocity in negative x-direction 

(b) Particle located at D has zero velocity 

(b) Particles located between B and C are under compression 

(d) None of the above

Answer 1

The correct option (d) None of the above

Explanation:

Velocity of particle is given by

vp = - v(dy/dx)

Here, v is wave speed and dy/dx the slope.

Hence, vP ∝ – slope

At point E, slope is positive, thereforce, vP will be in negative x-direction. Similarly, slope at D is zero or vP at D is zero.

Excess pressure P = – Bdy/dx

(B = bulk modulus)

In the region between B and C, slope is negative. Therefore, P is positive. Hence, particle lying between B and C are in compression.