Looking for classes? Ksquare Career Institute, Bengaluru →
Which one of the following statements is true :
A
Both light and sound waves in air are transverse
B
The sound waves in air are longitudinal while the light waves are transverse
C
Both light and sound waves in air are longitudinal
D
Both light and sound waves can travel in vacuum
Detailed Solution
Sound waves in air travel as compressions and rarefactions; the particles of air vibrate along the direction of propagation. So sound waves in air are longitudinal.
A gas cannot sustain shearing stress, so transverse mechanical waves cannot travel through air.
Light waves are electromagnetic waves, in which the electric and magnetic fields oscillate perpendicular to the direction of propagation. So light waves are transverse; this is shown by the fact that light can be polarised.
Sound is a mechanical wave and needs a material medium, so it cannot travel in vacuum, while light can.
So the true statement is that the sound waves in air are longitudinal while the light waves are transverse.
A gas cannot sustain shearing stress, so transverse mechanical waves cannot travel through air.
Light waves are electromagnetic waves, in which the electric and magnetic fields oscillate perpendicular to the direction of propagation. So light waves are transverse; this is shown by the fact that light can be polarised.
Sound is a mechanical wave and needs a material medium, so it cannot travel in vacuum, while light can.
So the true statement is that the sound waves in air are longitudinal while the light waves are transverse.