Each of the two strings of length 51.6 cm and 49.1 cm are tensioned separately by 20 N force. Mass per unit length of both the strings is same and equal to 1 g/m. When both the strings vibrate simultaneously the number of beats is :

Options

A. 7
B. 8
C. 3
D. 5

Answer

A

Explanation

Use V = `sqrt(T// m ) and v_(1) = (V)/(lambda_(1)) `
and `v_(2) = V//lambda_(2) therefore b = | v_(1) - v_(2) | . `
correct choice is a .