Class 12 Physics
CBSE and UP Board
Alternating Current
Chapter-7 Exercise 7.5
NCERT Solutions for Class 12 Physics Chapter 7 Question 5
In Exercises 7.3 and 7.4, what is the net power absorbed by each circuit over a complete cycle. Explain your answer.
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In the inductive circuit,
rms value of current, I = 15.92 A
rms value of voltage, V = 220 V
Hence, the net power absorbed can be obtained by the relation,
P = VI cos φ
Where, φ = Phase difference between V and I.
For a pure inductive circuit, the phase difference between alternating voltage and current is 90° i.e., φ= 90°.
Hence, P = 0 i.e., the net power is zero.
In the capacitive circuit, rms value of current, I = 2.49 A, rms value of voltage, V = 110 V Hence, the net power absorbed can be obtained as:
P = VI Cos φ
For a pure capacitive circuit, the phase difference between alternating voltage and current is 90° i.e.,
φ = 90°.
Hence, P = 0 i.e., the net power is zero.