# Waves - Online Test

Q1. In wave propagation
Explaination / Solution:

because in wave propagation particles only moves in perodic motion, particles get collide with their neighbouring particles then transfer energy to them and comes back to their normal stage. Now next particle which gain energy get into excited state and starts moving periodically and get collide to next adjacent particle and so on. Thus in wave propagation particles only transfer their kinetic energy and momentum. Hence particles does not move therefore there is no flow of matter but there is movement of disturbance.

Q2. When we make a mobile telephone call to a friend
Explaination / Solution:

Because mobile communication is a space communication and in space communication basically electromagnetic waves are used (as carrier waves as in case of radio communication) because of the modulation ( frequency, amplitude) operations which can be performed on EM waves. Thus when our friend receives the call, he also receives EM waves which is the carrier of our audio signals.

Q3. Electromagnetic waves are different from sound waves in that
Explaination / Solution:

Electromagnetic waves are transverse waves, they move perpendicular to the direction of propagation of wave ( the direction in which energy is transferred) and EM waves( Electromagnetic waves) can travel in vacuum, thus doesn't require any medium also.

Q4. Matter waves are useful in
Explaination / Solution:

Matter waves are also termed as De Broglie waves because they were initially introduced by him. All matters behave like a wave (during motion) and in there propagation there is action of forces due to collision between the particles, some time torque also exists, hence all the matters waves were consider to be a helpful part for understanding quantum.

Q5. The quantity similar to extension or compression of the spring in sound wave propagation (air) is
Explaination / Solution:

As in air wave propagates in the form of compression (increase in density of air) and rarefaction (decrease in density of air).

Q6. in transverse waves, the constituents of the medium
Explaination / Solution:

In transverse wave motion medium particles oscillates or vibrates in a direction perpendicular to the direction of wave propagation to form crest & trough in the wave motion.

Q7. in longitudinal waves, the constituents of the medium
Explaination / Solution:

In longitudinal wave motion, medium particles oscillates or vibrates in same direction of wave propagation to produce compression & rarefaction in wave propagation.

Q8. Travelling or progressive wave
Explaination / Solution:

As progressive wave means a wave propagating in some onward direction in the medium

Q9. The waves on the surface of water are of two kinds:.
Explaination / Solution:

As capillary & gravity waves are elastic waves or mechanical waves which require medium for their propagation. Hence they are using the elastic behaviour of water. Hence The waves on the surface of water are of two kinds: capillary waves and gravity waves

Q10. in the same medium transverse and longitudinal waves
Explaination / Solution:

As speed of transverse & longitudinal waves depend on different modulus of elasticity (Young's modulus, Bulk modulus, Modulus of Rigidity) of the medium. So in the same medium transverse and longitudinal waves travel with different speeds