The current drawn by the primary of a transformer, which steps down 200 V to 20 V to operate a device of resistance 20 Ω . is (Assume the efficiency of the transformer to be 80 %)

Question

The current drawn by the primary of a transformer, which steps down 200 V to 20 V to operate a device of resistance 20 Ω . is (Assume the efficiency of the transformer to be 80 %) (A) 0.125 A (B) 0.225 A (C) 0.325 A (D) 0.425 A

Tardigrade Admin · Accepted Answer

Given: Vp = 200 V, R = 20 Ω, Vs=20 V, η = 80 % Current through the secondary coil is Is=(Vs/R) =(20 V/20 Ω) =1 A Efficiency of transformer η=(Output power/Input power)=(VsIs/VpIp) or Ip=(Vs Is/Vp η) =(20×1×100/200×80) =0.125 A

Q. The current drawn by the primary of a transformer, which steps down $200 V$ to $20 V$ to operate a device of resistance $20 Ω$ . is (Assume the efficiency of the transformer to be $80 %$ )

$0.125 A$

$0.225 A$

$0.325 A$

$0.425 A$

Q. The current drawn by the primary of a transformer, which steps down 200V to 20V to operate a device of resistance 20Ω. is (Assume the efficiency of the transformer to be 80%)

0.125A

0.225A

0.325A

0.425A

Given: Vp​=200V, R=20Ω, Vs​=20V, η=80% Current through the secondary coil is Is​=RVs​​ =20Ω20V​ =1A Efficiency of transformer η=InputpowerOutputpower​=Vp​Ip​Vs​Is​​ or Ip​=Vp​ηVs​Is​​ =200×8020×1×100​ =0.125A

Q. The current drawn by the primary of a transformer, which steps down $200 V$ to $20 V$ to operate a device of resistance $20 Ω$ . is (Assume the efficiency of the transformer to be $80 %$ )

$0.125 A$

$0.225 A$

$0.325 A$

$0.425 A$