Question

Figure shows four identical blocks connected with massless springs on a frictionless horizontal plane. If block $A$ is given a push towards right, then:
(assume blocks do not lose the contact with surface)

• A. A small longitudinal wave will form
• B. A small transverse wave will form
• C. A small non-mechanical wave will form
• D. A small three dimensional wave will form

Answer 1

The correct option is A A small longitudinal wave will form

When block $A$ is pushed towards right, then due to elastic property of springs, block $B$ will also get displaced to right. Similarly, blocks $C$ and $D$ will get displaced to right.

After a while, all blocks will get displaced towards left and disturbance is transferred towards left.

As blocks are in periodic motion about their mean position along the direction of propagation of wave, we can say that the wave formed is a longitudinal wave.
Since the wave travels in a medium (the springs), it can't be non-mechanical. Also, it's not a three dimensional wave since it travels in the plane of the springs and blocks.
Hence, option (a) is correct.