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)

$\left|\text{dq}\right| = \frac{\text{d} \phi}{\text{R}} = \text{idt} = \text{Area under i-t graph}$
$∴ \, \text{d} \phi = \left(\text{Area under i-t graph}\right) \left(\text{R}\right)$
$= \frac{1}{2} \left(4\right) \left(\text{0.1}\right) \left(1 0\right) = 2 \text{ Wb}$