Question

The figure shows a part of a complete circuit. The potential difference $V_B-V_A$ when the current i is $5$A and is decreasing at a rate of ${10}^{3}A{s}^{-1}$ is given by.

• A. $15$V
• B. $10$V
• C. $-15$V
• D. $20$V

Answer 1

The correct option is C $-15$V

Solution:-

Given:-

R=2$\Omega$, I=5A, R=1$\Omega$, V=15V, L=5mH $\frac{dI}{dt}={10}^{3}A{s}^{-1},\frac{dI}{dt}=-100$

Using Kirchoff's law

$V+IR-L\frac{dI}{dt}=V_B-V_A$

$V_B-V_A=5\left(1\right)+15-5\times {10}^{-3}\times {10}^3(-100)$

$V_B-V_A=15V$