Question

A tuning fork is placed near a vibrating stretched wire. If frequency of tuning fork is greater than frequency of stretched wire, then a boy standing near the two hears a beat frequency f.

$\begin{array}{cc}\text{Column I}& \text{Column II}\\ \text{(A) If tuning fork is loaded with wax}& \text{(p) Beat frequency must increase}\\ \text{(B) If prongs of tuning fork are filed}& \text{(q) Beat frequency must decrease}\\ \text{(C) If tension in stretched wire is increased}& \text{(r) Beat frequency may increase}\\ \text{(D) If tension in stretched wire is decreased}& \text{(s) Beat frequency may decrease}\end{array}$

• A. A –p, B –s, C –rs, D -p
• B. A –q, B –p, C –rs, D -p
• C. A –rs, B –p, C –rs, D -p
• D. A –p, B –q, C –rs, D -p

Answer 1

The correct option is C

A –rs, B –p, C –rs, D -p

If fork loaded with wax the frequency may increase or decrease.

If the tension in the string increases then the frequency may increase or decrease.

If fork is filed or string tension decreases then the beat frequency always increases.