True or false questions. 1. Assuming that the temperature of the air is held con
ID: 1655233 • Letter: T
Question
True or false questions.
1. Assuming that the temperature of the air is held constant, the speed of sound in air does depend on the air pressure, to a good approximation.
2. If an air-filled tube of length L is closed at both endsand vibrates in a sound wave normal mode, the wavelength of the mode must satisfy the condition n(/2)=L, where n is a non-negative integer.
3. If an air-filled tube of length L is closed at both ends and vibrates in a sound wave normal mode, the oscillation of the air pressure in the tube musthave a node at both ends of the tube.
4. In a sound wave, there is only a vibration of pressure; there is no vibration of displacement like there is for a vibrating string.
Explanation / Answer
1. speed of sound in air = sqroot(gamma*RT)
where gamma and R are constants, and given T is constant so speed of sound does not depend on pressure for constant temperature
hence this statement is false
2. For closed closed tube
L = lambda/2, lambda, lambda*3/2 ...
L = lambda*n/2
lambda = 2L/n
hence true
3. as there is displacement node at the ends of closed closed tube, there has to be a pressure antinopde at this point
so this statement is false
4. There is vibration of air molecules, which is seen as pressure displacement, so this statement is false