Question

Magnetic flux in the circuit containing a coil of resistance 2 ohm changes from 2.0 wb to 10 wb in 0.2 sec. the charge passed through the coil in this time is

• A. 0.8 C
• B. 1.0 C
• C. 5.0C
• D. 4.0C

Answer 1

The correct option is D 4.0C

Given: Resistance of coil= 2 ohm

Initial magnetic flux= 2 wb

Final magnetic flux= 10wb

Solution: According to the law of electromagnetic induction,

induced emf=change in magnetic flux

$E=\frac{\partial \varphi }{\partial t}$

putting the values we get,

$\frac{(10-2)}{0.2}$

=40

Also, E=IR

$I=\frac{40}{2}$

I= 20A

Now, Q=It

Q= 20$\times$0.2

=4C

Hence, the correct option is (D).