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

Induced emf, `|e|=(Deltaphi)/(Deltat)=((2-1)(0.01))/(10^(-3))=10V`
`therefore` Current, `i=(e)/(R)=10^(3)A`
Heat produced, H = eit = `(10)(10^(3))(10^(-3))=10J`