Question

Sliding contact in circuit shown in figure, is moved to right continuously so that the resistance in the circuit is continuously increasing. Value of resistance at the instant shown is $8\Omega$. Now which of the following is correct?

• A. Current in the circuit is $2.0A$
• B. Current in the circuit is greater than $2.0A$
• C. Current in the circuit is less than $2.0A$
• D. Data is insufficient

Answer 1

Answer: (B)

As Resistance, $R$ is increasing,
So, steady state current is decreasing
$\Rightarrow i$, current is decreasing.

Applying kirchoff's law
$+E-\frac{Ldi}{dt}-iR=0$
$\Rightarrow 16+\left|\frac{Ldi}{dt}\right|=iR=8i$
$\Rightarrow i=\frac{16+|\frac{Ldi}{dt}|}{8}=$ greater than $2A$