Question

One $(10W,60Volt)$ bulb is to be connected to $100VA.C$ line. The required induction coil has self-inductance of value $(f=50Hz)$:

• A. $0.052H$
• B. $2.42H$
• C. $16.2mH$
• D. $1.62mH$

Answer 1

The correct option is A $0.052H$

Formulae,

$V=\sqrt{V_R^2+V_L^2}$

$\Rightarrow {100}^2={10}^2+V_L^2$

$\therefore V_L=99.5V$

$i=\frac{P}{V}=\frac{60}{10}=6A$

$V_L=i{X}_L$

$=i\left(2\pi \upsilon L\right)$

$99.5=6\times 2\times 3.14\times 50\times L$

$\therefore L=0.052H$