Question

Stethoscope works on the principle of sound.
A. Refraction
B. Echo
C. Multiple reflection
D. None of the above

Answer 1

Hint: To give the proper answer we have to know about all these options given in this question above. Then only we can give a proper answer. Now, refraction is the change in direction of a wave from one medium to another. There can be more than two mediums. Light waves frequently change their direction while travelling from one medium to another medium. Like light rays or light waves, sound waves and water waves also do the same.

Complete answer:
We have to know about echo also. When a sound is heard repeatedly as it goes and hit any surface and comes back to the initial position is called echo. And lastly reflection means when any wave hits any surface and then comes back to its initial medium instead of going through the medium and performing refraction.

A stethoscope is used to examine any patient physically. This is a medical instrument. Through this doctors listen to the sounds of beating heart and other sounds also produced within anyone’s body. So, this stethoscope works on the principle of multiple reflection.

So, the right answer is option C.

Note: We can get confused between echo and multiple reflection. Both mean the same apparently. But, there is a huge difference. In echo, we can hear a sound repeatedly which is caused by reflection, but multiple reflection means the sound waves or any light waves reflect more than one. And in this reflection the angle of incident and the angle of reflection will be the same always.