The network shown in the figure is a part of complete circuit. What is the potential difference `V_B-V_A` when the current `I` is `5 A` and is decreasing at a rate of `10^3A//s`?

Options

A. 5 V
B. 10 V
C. 15 V
D. 20 v

Answer

C

Explanation

Here, `i= 5A`
`(di)/(dt) = - 10^(3) A//s` (minus sign for decrease)
Applying Krichhoff's 2nd Law to the given circuit in Fig. we get
`V_(A) - iR + 15 - L (di)/(dt0 = V_(B)`
`V_(A) - 5 xx 1 + 15 - (5 xx 10^(-3)) (-10^(3)) = V_(B)`
`V_(A) + 15 = V_(B)`
or `V_(B) - V_(A) = 15 ` volt