Pyq- Electromagnetic Induction & Alternating Currents L-5

Question: A $12 \mathrm{~V}, 60 \mathrm{~W}$ lamp is connected to the secondary of a step down transformer, whose primary is connected to ac mains of $220 \mathrm{~V}$. Assuming the transformer to be ideal, what is the current in the primary winding? (NEET-2023)#

A) $2.7 \mathrm{~A}$

B) $3.7 \mathrm{~A}$

C) $0.37 \mathrm{~A}$

D) $\quad 0.27 \mathrm{~A}$

Answer: $\quad 0.27 \mathrm{~A}$#

Explanation#

$\mathrm{V}{\mathrm{s}} \mathrm{I}{\mathrm{s}}=\mathrm{V}{\mathrm{p}} \mathrm{I}{\mathrm{p}} \text { (ideal Transformer) }$

$\Rightarrow \mathrm{P}{\text {out }}=\mathrm{P}{\text {in }}$

$\Rightarrow 60=220 \times I_P$

$\mathrm{I}_P=\frac{60}{220}=0.27 \mathrm{~A}$