Question

which of the following waves have smallest velocity in vacuum
A sound
B micro
C ultraviolet
D infrared

Answer 1

answer :- option (A)

explanation :- as you know, micro, ultraviolet and infrared waves are electromagnetic wave. and all theses waves have constant velocity in vaccum. e.g., 3 × 10^8 m/s

but in case of sound wave, it doesn't move in vaccum. as we know, to propagate sound wave, medium is needed. hence, velocity of sound in vaccum = 0 m/s

so, option (a) is correct choice.

Answer 2

Hello,

Statement: which of the following waves have smallest velocity in vacuum.

Answer: A sound

Explanation :- Micro, Ultraviolet and Infrared waves are electromagnetic in nature. This means that these waves consist of constant velocities in vacuum which is equal to 3*10^8 m/s. But sound waves are different as they require a medium in order to propagate. The velocity of sound waves in vacuum is equal to zero. therefore this proves that the velocity of sound waves is smallest.

I hope the answer is helpful.

Thanks