In Melde's experiment, the string vibrates in 4 loops when a 50 gram weight is placed in the pan of weight 15 gram . To make the string to vibrates in 6 loops the weight that has to be removed from the pan is

Options

A. `0.0007` kg-wt
B. `0.0021` kg-wt
C. `0.036` kg-wt
D. `0.0029` kg-wt

Answer

C

Explanation

Frequency of vibration of string is given by
`n=(rho)/(2l)sqrt((T)/(m))`
`impliespsqrtT=` constant
`implies(p_(1))/(p_(2))=sqrt((T_(2))/(T_(1)))`
Hence, `4/6=sqrt((T_(2))/((50+15)g-"force"))`
`impliesT_(2)=28.8g-wt`
Hence, weight removed from the pan
`=T_(1)-T_(2)=65-28.8`
`=36.2"g-force"`
`=0.036` kg-wt