question_answer

The network shown in the figure is a part of a complete circuit. If at a certain instant the current i is 5 A and is decreasing at the rate of \[{{10}^{3}}A/s\] then \[{{V}_{A}}-{{V}_{B}}\] is

A)             5 V

B)             10 V

C)             15 V

D)             20 V

Correct Answer: C

Solution :

            By using Kirchoff?s voltage law                    \[{{V}_{A}}-i\ R+E-L\frac{di}{dt}={{V}_{B}}\Rightarrow {{V}_{B}}-{{V}_{A}}=15\ volt.\]