Question

A circular coil of radius $8.0cm$ and $20$ turns is rotated about its vertical diameter with an angular speed of $50rad{s}^{-1}$ in a uniform horizontal magnetic field of magnitude $3.0\times {10}^{-2}T$. Obtain the maximum and average emf induced in the coil. If the coil forms a closed loop of resistance $10\Omega$ , calculate the maximum value of current in the coil. Calculate the average power loss due to Joule heating. Where does this power come from?

Answer 1

Maximum induced emf $e=N\omega AB$;

$N=no.ofturns,\omega =angularspeed,A=Areaofcoil,B=Magneticfield$

$\Rightarrow e=0.603V$

Over a full cycle, the average emf induced in the coil is zero.

Maximum current, $I=e/R=0.0603$

Average power loss due to joule heating is $P=\frac{eI}{2}=0.018W$