NEET UG PHYSICS MCQ: ALTERNATING CURRENT

1 Medium

1 of 1

Analyzing +4 | -1

An ac source of angular frequency

\omega

is fed across a resistor

r

and a capacitor

C

in series. The current in the circuit measured is

l

. If now the frequency of source is changed to

\omega / 3

(but maintaining the same voltage), the current in the circuit is found to reduce by a factor of three. The power factor of the circuit at the original frequency

\omega

View answer and explanation

Correct option: C

Zero

Option C (Zero) is correct because the problem states the current reduces by a factor of 3 when the frequency is reduced to

\omega/3

, implying resonance at the original frequency.

More Questions from ALTERNATING CURRENT

Practice All Chapter MCQs →

Assertion (A) : In an

\mathrm{AC}

circuit, potential difference across the capacitor may be greater than the applied voltage.

Reason (R) :

V_C=I X_C

, whereas

V=I Z

and

X_C

can be greater than

Z

also. When power is drawn from the secondary coil of the transformer, the dynamic resistance An alternating e.m.f. is applied to purely capacitive circuit. The phase relation between e.m.f. and current flowing in the circuit is or
In a circuit containing capacitance only
Average power in the L-C-R circuit depends upon A generator produces a voltage that is given by

V = 240\sin 120\;t

, where t is in seconds. The frequency and r.m.s. voltage are In a choke coil, the resistance

{X_L}

and resistance

R

are such that