Question

A transformer connected to 220V line shows an output of 2A at 11000V. The efficiency is 100%. The current drawn from the line is:
A. 100A
B. 200A
C. 22A
D. 11A

Answer 1

Hint: A transformer is a converting device that is used to change the voltage of alternating current from one value to another. It can be step up type or step down type depending upon the need of utilization and it works on the criteria of magnetic induction.

Complete step by step answer:
Apply the condition of the transformer with 100% efficiency.
${V_s}{I_s} = {V_P}{I_P}$
Here VS is the voltage on secondary side, Is is the current on the secondary side, VP is the voltage on the primary side, IP is the current on the primary side.
Substitute 220 V for VP, 2A for IS, 11000V for Vs to find the value of IP.
$\begin{array}{c}
11000V \times 2A = 220V \times {I_P}\\
{I_P} = 100A
\end{array}$
Therefore, the current drawn from the line is 100 A.

So, the correct answer is “Option A”.

Note:
When the voltage from primary to secondary side is increased then it is known as a step up transformer. When the voltage from primary to secondary side is decreased then it is known as step down transformer.