Question

In a circuit a coil of resistance $2\Omega$, then magnetic flux charges from $2.0Wb$ to $10.0Wb$ in $0.2sec.$ The charge flow in the coil during this time is:

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

Answer 1

The correct option is B $4.0C$

The relation between the rate of change of charge (or current) and the flux is given by the following relation:

$\because \frac{dQ}{dt}=-\frac{1}{R}\frac{d\varphi }{dt}$

$\frac{dQ}{dt}=\frac{-(10-2)}{2}=4C$