Question

(a) : 

1. What are mechanical waves? 

2. Name one property of waves that do not change when the wave passes from one medium to another. 

The diagram above shows three different modes of vibrations P, Q and R of the same string. 

1. Which vibrations will produce a louder sound and why? 

2. The sound of which vibration will have maximum shrillness?

3. State the ratio of wavelengths P and R.

Answer 1

(a) : 

1. Mechanical Waves : “Sound waves which require medium to travel are called Mechanical Waves.” 

2. Frequency of wave does not change as it passes from one medium to other medium. 

(b) : 

1. R will produce louder sound because its amplitude is more than P and Q. 

2. The sound of P string will have maximum 

3. The ratio of wavelength of P and R is l_p /l_R = f_R/f_p = 1/3 

∴ l_p : l_R = 1 : 3