If we put a cardboard (say 20 cm × 20 cm) between a light source and our eyes, we can’t see the light. But when we put the same cardboard between a sound source and out ear, we hear the sound almost clearly. Explain.
Answers
Yes we cannot see the light when a cardboard is inserted in between us and object because :
---> Light has rectilinear propagation unlike sound waves.
----> When we put a cardboard between the light source and our eyes, the light waves are obstructed by the cardboard and cannot reach our eyes,
--->which doesn’t happen when the cardboard is inserted between sound source and our ear .
Question :-
If we put a cardboard (say 20 cm × 20 cm) between a light source and our eyes, we can’t see the light. But when we put the same cardboard between a sound source and out ear, we hear the sound almost clearly. Explain.
Answer :-
If we put the cardboard between light source and receiver , then we cannot see the light .
This is because the body is opaque and does not let light to pass through it.
Also light is an electromagnetic wave which travels in a straight path only.
Sound waves can travel sideways also and it is not always in straight path .
Thus sound can be heard . The chief reason is that sound needs material medium and it is a transverse wave which means it can travel perpendicular to the surface .