Question

In a coil of self inductance 0.5 henry, the current varies at a constant rate from zero to 10 amperes in 2 seconds. The e.m.f. generated in the coil is

• A. 10 volts
• B. 5 volts
• C. 2.5 volts
• D. 1.25 volts

Answer 1

Answer: (C)

2.5 volts

Answer 2

$\frac{\Delta i}{\Delta t} = \frac{10}{2} = 5\mspace{6mu} A/\sec$ ⇒ $e = L\frac{\Delta i}{\Delta t} = 0.5 \times 5 = 2.5\mspace{6mu} volts$