Question

The extension in a string, obeying Hooke’s law, is x. The speed of sound in the stretched string is v. If the extension in the spring is increased to 1.5x, the speed of sound will be ___________

(a) 1.22v

(b) 0.16v

(c) 1.50v

(d) 0.75v

The question was asked during an online exam.

My doubt is from Transverse Waves in section Waves of Engineering Physics I

Answer 1

Right option is (a) 1.22v

The explanation: According to Hooke’s law,

Tension (T) is proportional to Extension (x)

Also, speed of sound,

v∝√T

v^‘∝√1.5x

v^‘/v=√1.5=1.22

v^‘=1.22v.