Two identical stringed instruments have frequency 100 Hz . If tension in one of them is increased by 4% and they are sounded together then the number of beats in one second is

Options

A. 1
B. 8
C. 4
D. 2

Answer

D

Explanation

Frequency of vibratation in tight string
`n = (p)/(2l) sqrt((T)/(m)) implies n infty sqrt(T)`
`(Deltan)/(n) = (DeltaT)/(2T) = (1)/(2) xx(4%) = 2%`
Number of beats = `Deltan = (2)/(100) xx n = (2)/(100) xx 100 = 2`