Question

The time period of sound is increased by 4 times. Find the ratio of the new speed to the old speed.

• A. 1
• B. 2
• C. 4
• D. 8

Answer 1

The correct option is A 1

Speed of sound in a medium is a characteristic of the medium and temperature.
$v\propto \frac{\sqrt{T}}{\sqrt{\rho M}}$
where:
v: Speed of sound
T: Temperature
$\rho :$ Density
M: Molecular Mass of the medium

Increasing time period decreases the frequency of the wave.
$v=f\lambda$ still holds because wavelength increases to maintain the speed of the wave in the medium.