Class 12 Physics
CBSE and UP Board
Alternating Current
Chapter-7 Exercise 7.4
NCERT Solutions for Class 12 Physics Chapter 7 Question 4
A 60 μF capacitor is connected to a 110 V, 60 Hz ac supply. Determine the rms value of the current in the circuit.
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Capacitance of capacitor, C = 60 μF = 60 x 10-6 F
Supply voltage, V = 110 V
Frequency, ν = 60 Hz
Angular frequency, ω= 2πν
Capacitive reactance,
XC = 1/ωC = 1/2πνC =1/ (2π x 60 x 60 x 10-6) Ω
rms value of current is given as :
I = V/XC = 110/(1/ (2π x 60 x 60 x 10-6) )
= 110 x (2π x 60 x 60 x 10-6)= 2.49 A
Hence, the rms value of current is 2.49 A.