A physicist works in a laboratory where the magnetic field is `2T`. She wears a necklace enclosing area `0.01 m^(2)` in such a way that the plane of the necklace is normal to the field and is having a resistance `R=0.01Omega`. Because of power failure, the field decays to `1T` in time `10^(-3)` seconds.
The what is the total heat produced in her necklace?`(T=tesla)`

Options

A. 10 J
B. 20 J
C. 30 J
D. 40 J

Answer

A

Explanation

`H=(V^(2))/(R)t=(e^(2))/(R)t`
Now `e=(AdB)/(dt)=(0.01xx1)/(10^(-3))=10V`
`therefore H=(100xx10^(-3))/(0.01)=10J`