Alternating Current

Given :
For Bulb B₁ :
P₁ = 60 W , V = 220 V

For Bulb B₂ :
P₂ = 100 W, V = 220 V

Required is R₁ + R₂ :

Now,



So, the correct option is (C) : 37.5 W

The relationship between the voltage and the current in an AC circuit with a capacitor is given by: where:
is the voltage across the capacitor,
is the current through the capacitor,
is the capacitive reactance. We are given:
, - .

The RMS value of the voltage and current are: Now, using the formula , we can solve for :

Thus, the capacitive reactance of the capacitor is , which is option (D).

The r.m.s. (root mean square) value of an A.C. current is related to the peak value of the current by the formula: Thus, the r.m.s. value of A.C. current is times the peak value, not times.
Therefore, statement (C) is incorrect.

Other statements are correct:
(A) The direction of eddy currents is indeed governed by Lenz's law.
(B) A choke coil is a pure inductor used to control the current in A.C. circuits.
(D) The quality factor is a measure of the sharpness of resonance in A.C. circuits.
(E) The energy stored in an inductor is correctly given by .

The correct option is (C) : The r.m.s. value of A.C. current is times the peak value of A.C. current.

Given parameters:

• Inductance
• Resistance
• Angular frequency

Condition for maximum current:

Capacitance calculation:

Thus, the correct option is (D): .