Question

When the length of the vibrating segment of a sonometer wire is increased by 1%, the percentage change in its frequency is?

(a) 100/101

(b) 99/100

(c) 1

(d) 2

The question was posed to me in unit test.

My question is based upon Travelling Waves topic in portion Waves of Engineering Physics I

Answer 1

Correct choice is (c) 1

Best explanation: v=1/2L×√(T/m)

For constant T and m,

∆v/v×100=∆L/L×100=1%

Frequency will decrease by 1%.