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A choke is preferred to a resistance for limiting current in an $A C$ circuit because

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Important Questions on Alternating Current

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Devices

For a given frequency, the inductive reactance of a coil at

100 H

25 Ω

. For the same frequency, the inductance reactance at

200 H

will be

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Devices

600 Hz

, an inductor and capacitor have equal reactances, the ratio of the capacitive reactance to the inductive reactance at

60 Hz

will be

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Devices

What happens to the inductive reactance and the current in a purely inductive circuit if the frequency is halved ?

MEDIUM

Physics>Electricity and Magnetism>Alternating Current>AC Devices

The phase difference between current and voltage in an A.C. circuit containing inductance only is.

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Devices

Choose the wrong statement for the pure inductive circuit.

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Devices

A pure inductor of,

30.0 mH

is connected to a source of,

250 V

. Find the inductive reactance (in

Ω

) and R.M.S. current (in

A

) in the circuit if the frequency of the source is

80 Hz

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Devices

Which of the following represents the variation of inductive reactance

(X_{L})

with the frequency of voltage source

(ν) ?

MEDIUM

Physics>Electricity and Magnetism>Alternating Current>AC Devices

The equation of current in a purely inductive circuit is

5 \sin (49 π t - 30 °)

. If the inductance is

30 mH

then the equation for the voltage across the inductor, will be

HARD

Physics>Electricity and Magnetism>Alternating Current>AC Devices

An inductance coil has a reactance of

100 Ω

. When an AC signal of frequency

1000 Hz

is applied to the coil, the applied voltage leads the current by

45 °

. The self-inductance of the coil is

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Devices

Three identical emf sources are attached to a single circuit element: a resistor, a capacitor, or an inductor. The current amplitude is then measured as a function of frequency. Which one of the following curve corresponds to inductive circuit?

Question Image

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Devices

The phase difference between voltage and current when an ac source is connected to an inductor. :

HARD

Physics>Electricity and Magnetism>Alternating Current>AC Devices

A voltage

V_{PQ} = V_{0} \cos (ωt)

(where,

V_{0}

is a real amplitude) is applied between the points

P

and

Q

in the network shown in the figure. The values of capacitance and inductance are

C = \frac{1}{ω R \sqrt{3}}

and

L = \frac{R \sqrt{3}}{ω}

. Then, the total impedance between

P

and

Q

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Devices

Given below are two statements :
Statement-I: The reactance of an AC circuit is zero. It is possible that the circuit contains a capacitor and an inductor.
Statement-II: In AC circuit, the average power delivered by the source never becomes zero.
In the light of the above statements, choose the correct answer from the options given below

HARD

Physics>Electricity and Magnetism>Alternating Current>AC Devices

In the given circuit the $AC$ source has $ω = 100 rad s^{- 1}$ . Considering the inductor and capacitor to be ideal, what will be the current $I$ flowing through the circuit?

Question Image

MEDIUM

Physics>Electricity and Magnetism>Alternating Current>AC Devices

A sinusoidal voltage

V (t) = 210 \sin 3000 t

volt is applied to a series LCR circuit in which

L = 10 mH, C = 25 μF

and

R = 100 Ω

. The phase difference

(Φ)

between the applied voltage and resultant current will be

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Devices

An alternating voltage source

V = 260 \sin (628 t)

is connected across a pure inductor of

5 mH

. Inductive reactance in the circuit is:

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Devices

A coil of inductance

0.1 H

and resistance

110 Ω

is connected to a source of

110 V

and

350 Hz

. The phase difference between the voltage maximum and the current maximum is

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Devices

A sinusoidal voltage with a frequency of

50 Hz

is applied to a series

L C R

circuit with a resistance of

5 Ω

, inductance of

20 mH

and a capacitance of

500 μ F

. The magnitude of impedance of the circuit is close to

EASY

Physics>Electricity and Magnetism>Alternating Current>AC Devices

A series

L R

circuit is connected to a voltage source with

V (t) = V_{0} \sin (ω t)

. After a very large time, current

I (t)

behaves as

(t_{0} ≫ \frac{L}{R})

MEDIUM

Physics>Electricity and Magnetism>Alternating Current>AC Devices

A resistance

R

draws power

P

when connected to an

AC

source. If an inductance is now placed in series with the resistance, such that the impedance of the circuit becomes

Z

, the power drawn will be:

A choke is preferred to a resistance for limiting current in an AC circuit because

Important Questions on Alternating Current

Learn and Prepare for any exam you want !

A choke is preferred to a resistance for limiting current in an $A C$ circuit because