A 220 ~V input is supplied to a transformer. The output circuit draws a current of 2.0 ~A at 440 ~V . If the efficiency of the transformer is 80 \% , the current drawn by the primary windings of the transformer is

Correct answer: D. 5.0 ~A Efficiency is defined as the ratio of output power and input power ie, aligned \% & = P_ out P_ in ×100= V_s i_s ~V_ p i_ p ×100 80 & = 2 × 440 220 × i_ p ×100 i_ p & =5 ~A aligned

NEET 2010

Exam: NEET
Year: 2010
Subject: Physics
Chapter: Alternating Current

NEET 2010 · Physics · Alternating Current

A 220 ~V input is supplied to a transformer. The output circuit...

220 \mathrm{~V}

input is supplied to a transformer. The output circuit draws a current of

2.0 \mathrm{~A}

440 \mathrm{~V}

. If the efficiency of the transformer is

80 \%

, the current drawn by the primary windings of the transformer is

Options

A $3.6 \mathrm{~A}$
B $2.8 \mathrm{~A}$
C $2.5 \mathrm{~A}$
D $5.0 \mathrm{~A}$

Correct answer

D. $5.0 \mathrm{~A}$

Step-by-step solution

Efficiency is defined as the ratio of output power and input power

\text{ ie, }

\begin{aligned} \eta\% & =\frac{\mathrm{P}_{\text{out }}}{\mathrm{P}_{\text{in }}} \times100=\frac{\mathrm{V}_s \mathrm{i}_s}{\mathrm{~V}_{\mathrm{p}} \mathrm{i}_{\mathrm{p}}} \times100 \\ 80 & =\frac{2 \times 440}{220 \times \mathrm{i}_{\mathrm{p}}} \times100 \\ \Rightarrow \quad \mathrm{i}_{\mathrm{p}}& =5 \mathrm{~A} \end{aligned}

Practice Alternating Current on Quantrex Academy →

More from Alternating Current