Question

A circular wire loop 51 cm in diameter has resistance 120 ω and lies in a horizontal plane. a uniform magnetic field points vertically downward, and in 25 ms it increases linearly from 5.0 mt to 55 mt. part a find the magnetic flux through the loop at the beginning.

Answer 1

The radius of the wire loop is $r= \frac{51 cm}{2}= 25.5 cm=0.255 m$, so the area enclosed by the loop is
$A=\pi r^2 = \pi (0.255 m)^2=0.204 m^2$

Initially, the magnetic field intensity is B=5.0 mT=0.005 T, so the magnetic flux throug the wire loop is
$\Phi = BA=(0.005 T)(0.204 m^2)=1.02 \cdot 10^{-3} Wb$