Ncert Exercises & Solutions

During the propagation of a plane progressive mechanical wave,

(a) all the particles are vibrating in the same phase.

(b) the amplitude of all the particles is equal.

(d) the wave velocity depends upon the nature of the medium.

Choose the correct alternatives:

1. (a, b, d)

2. (a, c)

3. (b, c, d)

4. (c, d)

(3) Hint: Use the concept of mechanical wave.

Step 1: Analyse each option.

During propagation of a plane progressive mechanical wave, like shown in the diagram, the amplitude of the particles is equal.

i. Clearly, the particles O, A and B are different phases.

ii. The particles of the wave shown in the figure are having up and down SHM.

iii. For progressive wave propagation in a fluid, speed =

v = \sqrt{\frac{B}{ρ}}

Hence,

ν \propto \sqrt{\frac{1}{ρ}} [∵ B is constant]

ρ

depends on the medium, hence v also depends upon the nature of the medium.