Q172 / 180 · COMEDK 2024 (Memory Based) · Physics

A step down transformer is used to reduce the main supply of 220 V to 10 V . If the primary draws 5 A and secondary 88 A current, calculate the efficiency of the transformer.

A
$40 \%$
B
$60 \%$
Correct answer
C
$80 \%$
D
$45 \%$

Solution

$e_p=220 \mathrm{~V}, e_s=10 \mathrm{~V}, I_p=5 \mathrm{~A}$ and $I_s=88 \mathrm{~A}$
Input power, $P_i=e_P \times I_P=220 \times 5=1100 \mathrm{~W}$
Output power, $P_o=e_s \times I_s=10 \times 88=880 \mathrm{~W}$
Efficiency, $\eta=\frac{P_0}{P_1}=\frac{880}{1100}=0.8$ or $80 \%$

Hence, the correct answer is option: 'C'.

Relevant Questions

When a current of 2.5 A passes through the primary coil of a transformer of 200 number turns, the magnetic flux linked with the secondary co09 May, 2026 (S2)Transformers
The ratio of the number of turns of the primary coil to the secondary coil of an ideal transformer is . The primary is connected to 220 V su10 May, 2025 (S2)Transformers
A power transmission line feeds input power at 2200 V to a step-down transformer with its primary windings having 2000 turns. The output pow10 May, 2025 (S3)Transformers
A transformer has 400 turns in its primary winding and 800 turns in its secondary winding. The primary voltage is and the load in the second2024 (Afternoon Shift)Transformers
A transformer of efficiency has 200 turns in the primary and 40000 turns in the secondary. It is connected to a main supply and secondary fe2024 (Evening Shift)Transformers
A transformer which steps down to is to operate a device having impedance . The current drawn by the primary coil of the transformer is :2024 (Morning Shift)Transformers