Question

Some magnetic flux is changed from a coil of resistance $10\Omega$ . As a result, an induced current is developed in it, which varies with time as shown in the diagram. The magnitude of change in flux through the coil in webers is

• A. $\text{2}\text{Wb}$
• B. $\text{4}\text{Wb}$
• C. $\text{6}\text{Wb}$
• D. $\text{8}\text{Wb}$

Answer 1

Answer: (A)

$\left|\text{dq}\right|=\frac{\text{d}\varphi }{\text{R}}=\text{idt}=\text{Area under i-t graph}$
$\therefore \text{d}\varphi =\left(\text{Area under i-t graph}\right)\left(\text{R}\right)$
$=\frac{1}{2}\left(4\right)\left(\text{0.1}\right)\left(10\right)=2\text{ Wb}$