What is the change in radius of ring ?

Options

A. `(qQ)/(8pi^2epsilon_0RAY)`
B. `(qQ)/(8piepsilon_0 RAY)`
C. `(qQ)/(4pi^2epsilon_0 RAY)`
D. None

Answer

A

Explanation

Longitudinal strain developed in the ring `(2piDeltaR)/(2piR)=(DeltaR)/R`
The area of cross section is A and so the longitudinal stress developed in the ring will be :
`T/A =((qQ)/(8pi^2 epsilon_0R^2))/A=(qQ)/(8pi^2 epsilon_0 R^2 A)`
Young.s modulus
(Y)=`"Stress"/"Strain"=((qQ)/(8pi^2epsilon_0R^2A))/((DeltaR)/(R))=(qQ)/(8pi^2 epsilon_0 RADeltaR)`
`rArr DeltaR=(qQ)/(8pi^2 epsilon_0 RAY)`