Question

If the current in the toroidal solenoid increases uniformly from zero to $6.0\, A$ in $3.0?s.$ Self inductance of the toroidal solenoid is $40?H$. The magnitude of self induced emf is

• A. $24V$
• B. $48V$
• C. $80V$
• D. $160V$

Answer 1

Answer: (C)

$80V$

Answer 2

Current in toroidal solenoid increases uniformly from 0 to $6.0\, A$ in $3.0 \mu s$.
Magnitude of self induced emf is given by
$|\varepsilon|=L\left|\frac{d i}{d t}\right|$
[Symbols have usual meanings]
$=\left(40 \times 10^{-6}\right)\left(\frac{6-0}{3.0 \times 10^{-6}}\right)=80\, V$