A conducting ring of mass 2 kg and radius 0.5 m is palced on a smooth horizationl plante . The ring carries a cuurent `i=4 A`. A horizationtal magnetic field B=10 T is initinal angular acceleration of the ring will be

Options

A. `40||rad//s^(2)`
B. `20||rad//s^(2)`
C. `5||rad//s^(2)`
D. `15||rad//s^(2)`

Answer

A

Explanation

`tau=IalphaimpliesMB=IalphaimpliesIpir^(2)B=1/2mr^(2)alpha`
`alpha=(2IBpi)/m, alpha=(2xx4xx10pi)/2=40pirad//s^(2)`