Q67 of 199 Page 186

When we put our ear to a railway line, we can hear the sound of an approaching train even when the train is far off but its dound cannot be heard through the air. Why?

Since sound travels faster m solids, we can hear the sound of train by putting our ear on the solid and only later we can hear though air.


More from this chapter

All 199 →
62

An electric bell is suspended by thin wires in a glass vessel and set ringing. Describe and explain what happens if the air is gradually pumped out of the glass vessel.

 62

Why cannot a sound heard on the moon? How do astronauts talk to one another on the surface of moon?

 67

How could you convince a small child that when you speak, it is not necessary for air to travel from your mouth to the ear of a listener?

 63

Define the terms ‘frequency’, ‘wavelength’ and ‘velocity’ of a sound wave. What is the relation between them?