Question

Wave which cannot travel in vacuum is-
A. Seismic wave
B. X-rays
C. Ultrasonic waves
D. Radio waves

Answer 1

The question given to us required the knowledge of different types of waves and also which kind of waves can travel in vacuum. Here, we will discuss mechanical waves and electromagnetic waves and their medium of propagation and also find which of the above waves is mechanical waves.

Complete step-by-step solution:
In order to solve the above question, we have to find which of these waves cannot travel in vacuum. So, let us first discuss mechanical waves and electromagnetic waves then only we will be able to come to the conclusion that which of the above waves cannot travel in vacuum.
Let us first discuss about mechanical waves
The mechanical waves are those waves that are the oscillation of the matter and are responsible for the transfer of energy through a medium that means they require a medium for travelling as the propagation of these waves happen because of stretching and compressing of the medium. This stretching and compressing cause the disturbance in the medium which is pushed forward by the vibrating particles of the medium for passing the energy to other particles and letting them oscillate. So, with the above discussion of mechanical waves we can clearly see that mechanical waves cannot travel without any medium that means they cannot travel in vacuum.
Now, let us talk about electromagnetic waves, they are the combination electric and magnetic waves that mean they do not require any medium for propagation and hence can travel in vacuum.
From the above options we know that seismic waves and mechanical waves and X-rays, ultrasonic rays and radio waves these three are electromagnetic waves that means seismic waves will require a medium for propagation and hence, cannot travel in vacuum.
So, option (A) seismic wave is the correct answer of the given question.

Note: From the above discussion we got to know that seismic waves require a medium for propagation that means cannot travel in vacuum. The other examples of the mechanical waves that cannot travel in vacuum are infrasonic waves, sound waves, vibrations, wind waves etc.