JEE Main202228 Jul 2022Evening ShiftPhysicsAlternating CurrentActual
A transformer operating at primary voltage 8 kV and secondary voltage 160 V serves a load of 80 kW . Assuming the transformer to be ideal with purely resistive load and working on unity power factor, the loads in the primary and secondary circuit would be
Options
- A800   Ω and 1 . 06   Ω
- B10   Ω and 500   Ω
- C800   Ω and 0 . 32   Ω
- D1 . 06   Ω and 500   Ω
Correct answer
C. 800   Ω and 0 . 32   Ω
Step-by-step solution
Since the transformer is assumed to be purely resistive, the power of the transformer can be calculated with P = V 2 R . Therefore, For the primary coil, P = 8 × 10 3 2 R P = 80 × 10 3   W ⇒ R P = 800   Ω For the secondary coil, P = 160 2 R S = 80 × 10 3   W ⇒ R S = 0 . 32 Ω