Question

How is the speed of sound in air affected by the temperature of air?
A. no effect
B. decrease with the increase in temperature
C. increase with the increase in temperature.
D. data insufficient

Answer 1

Sound wave is a longitudinal or pressure wave which travels in a medium due to the expansion and the compression of the particles in the medium. The velocity of sound waves indirectly depends on the energy of the particles as the particle with large energy moves faster. With the rise in temperature the energy of the particle also increases.

Complete answer:
A sound wave is a longitudinal wave or a pressure wave. Longitudinal waves can be defined as the wave where the particles in the medium where the wave is propagating move parallel to or in the direction of the wave. Now, if we consider the sound wave it propagates as the particles in the medium are compressed and expanded by the vibration in the direction of propagation of the vibration. The concept is similar to the propagation of the longitudinal wave. So, we can say that the sound wave propagates as a longitudinal wave.

Sound waves travel through the air by the compression and expansion waves. The compression or expansion wave in the small scale depends on the transfer of energy between the molecules in the air. As the temperature increases the molecules in the air acquire more energy and the molecules vibrate faster. Since the molecules vibrate faster, the sound wave travels through air faster because the sound wave is propelled by the collision of molecules in the air.

So, the correct answer is “Option C”.

Note:
Temperature of a system increases means that the heat energy of the system increases. Heat is a form of kinetic energy which increases the energy of the molecules in the medium and they vibrate faster as the heat energy increases i.e. with the increase in temperature of the system the molecules also vibrate faster.