3. The speed of the sound increases when there is an increase in the
1. temperature
2. moisture
Select the correct option from the codes given below:

[A] Only 1
[B] Only 2
[C] Both 1 & 2
[D] Neither 1 nor 2

2.Which of the following is / are correct statements?

1. When glass rod is rubbed with silk, negative charge develops on silk
2. When Ebonite rod is rubbed with fur, negative charge develops on fur

Select the correct option from the codes given below:

[A] Only 1
[B] Only 2
[C] Both 1 & 2
[D] Neither 1 nor 2

Which of the following actions will increase the speed of the sound in air?

(a) Decreasing the air temperature.

(b) Increasing the frequency of the sound

(c) Increasing the air temperature

(d) Increasing the amplitude of the sound wave.

(e) Reducing the pressure of air.

[A] Only 1 & 3
[B] Only 1, 3 & 4
[C] Only 2, 3 & 4
[D] Only 2 & 4