Question

Magnetic flux through a circuit of resistance $20\Omega$ is changed from 20 Wb to 40 Wb in 5 ms. Charge passed through the circuit during this time is

• A. 1 C
• B. 2 C
• C. Zero
• D. 0.5 C

Answer 1

The correct option is A 1 C

$R=10\Omega$

Since $e=-\frac{d\varphi }{dt}$, we get

$e=-\frac{20-40}{5\times {10}^{-3}}=4\times {10}^{3}V$

The current in the circuit is given by,

$i=\frac{e}{R}$

$\Rightarrow \frac{q}{t}=\frac{e}{R}$

$\Rightarrow q=\frac{4\times {10}^3\times 5\times {10}^{-3}}{20}=1C$