An AC voltage source of variable angular frequency and fixed amplitude V_0 is connected in series with a capacitance C and an electric bulb of resistance R (inductance zero). When is increased

JEE Advanced 2010 Physics question

An AC voltage source of variable angular frequency and fixed amplitude is connected in series with a capacitance C and an electric bulb of resistance R (inductance zero). When is increased

(A)the bulb glows dimmer
(B)the bulb glows brighterCorrect
(C)total impedance of the circuit is unchanged
(D)total impedance of the circuit increases

Answer: (B)

Solution

For a series RC circuit the impedance is . When increases, the capacitive reactance decreases, so Z decreases;

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Question ID VK-025794