ElectroMagnetic InductionHard
Question
The self inductance of a choke coil is 10 mH. when it is connected with it is connected with a 10 V D. C. source. source, then the loss of power is 20 watt. When it is connected with 10 volt A.C. source loss of power is 10 watt. The frequency of A.C. source will be : -
Options
A.50 Hz
B.60 Hz
C.80 Hz
D.100 Hz
Solution
R = 
= 5Ω
In AC circuit
P = VI cos φ =
cos φ = 
⇒ 10 =
⇒ ωL = 5Ω
⇒ ω =
⇒ f = 
=
= 80 Hz
= 5ΩIn AC circuit
P = VI cos φ =
cos φ = ⇒ 10 =
⇒ ωL = 5Ω⇒ ω =
⇒ f = =
= 80 HzCreate a free account to view solution
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