Question
Physics Question on Alternating current
A lamp consumes only 25% of the peak power in an ac circuit. The phase difference between the applied voltage and the current is
A
6π
B
3π
C
4π
D
2π
Answer
3π
Explanation
Solution
According to the equation,
P=10025E0I0
P=41E0I0=2×2E0I0 ...(i)
We know that, P=2E0I0cosϕ ...(ii)
On comparing Eqs. (i) and (ii), we get
cosϕ=21
ϕ=cos−1(21)
⇒ϕ=3π or 60∘