Free Printable ALTERNATING CURRENT

1.

All of the following have the same units except:

a)

inductance.

b)

capacitive reactance.

c)

impedance.

d)

resistance.

2.

A resistor is connected to an AC power supply. On this circuit, the current

a)

leads the voltage by 90°.

b)

lags the voltage by 90°.

c)

is in phase with the voltage.

d)

none of the given answers

3.

A pure inductor is connected to an AC power supply. In this circuit, the current

a)

leads the voltage by 90°.

b)

lags the voltage by 90°.

c)

is in phase with the voltage.

d)

none of the given answers.

4.

What is the phase angle between the voltages of the inductor and capacitor in a RLC series circuit?

a)

zero

b)

90°

c)

180°

d)

270°

5.

Which of the following diagrams is the correct phasor diagram for V_R,V_Land V?

a)

b)

c)

d)

6.

The formula for inductive reactance is

a)

$\frac{1}{\omega L}$

b)

$\omega C$

c)

$\frac{1}{\omega C}$

d)

$\omega L$

7.

The equations for alternating emf and alternating current in a circuit containing capacitor are

a)

$V\ =\ V_0\ \sin\ \omega t,\ I\ =\ I_0\ \sin\left(\omega t-\frac{\pi}{2}\right)$

b)

$V=V_0\ \sin\ \omega t\ ,\ I\ =\ I_0\ \sin\left(\omega t\ +\frac{\pi}{2}\right)$

c)

$V\ =\ V_0\ \sin\omega t,\ I\ =I_0\ \sin\ \omega t$

d)

$V\ =\ V_0\ \sin\left(\omega t\ +\frac{\pi}{2}\right),\ I\ =\ I_0\ \sin\ \omega t$

8.

What happens at resonance?

a)

Current is maximum

b)

Impedance is maximum

c)

Resistance is maximum

d)

Power factor is maximum

9.

A sine wave has a peak value of 354 V, What is the RMS value?

a)

250 V

b)

500 V

c)

354 V

d)

200V

10.

Which one of the below AC parameters show the effective Dc value?

a)

Peak Value

b)

RMS value

c)

Peak to peak value

d)

Frequency

11.

If an electric bulb is connected to an AC source, which of the following statement is true about the phase difference between the voltage across the bulb and current flowing in it?

a)

In phase.

b)

Not in phase.

c)

The voltage is leading the current.

d)

The current is leading the voltage.

12.

The r.m.s value of an alternating current is given by steady (D.C) current which when flowing through a given circuit for a given time produces

a)

the more heat than produced by A.C when flowing through the sam circuit

b)

the less heat than produced by A.C when flowing through the sam circuit

c)

the same heat than produced by A.C when flowing through the same circuit

13.

The sum of resistance and reactance is referred to as ________.

a)

geometric resistance

b)

conductance

c)

impedance

d)

susceptance

14.

The opposition to AC current flow presented by capacitors and inductors is called:

a)

Resistance

b)

Reactance

c)

Impedance

d)

Reluctance

15.

Inductive reactance results in a current that

a)

Leads the voltage by 90°

b)

Is in phase with the voltage

c)

Leads the voltage by π rad

d)

Lags the voltage by π/2 rad

16.

In RLC circuit, If R is the resistance, XL is the inductive reactance and XC is the capacitive reactance, the impedance Z of the circuit is:

a)

b)

c)

d)

17.

Which of the following statements about a series RCL circuit is true?

a)

At resonance, the total reactance and total resistance are equal.

b)

The impedance at resonance is purely inductive.

c)

The current flowing in the circuit at resonance is at maximum.

d)

The impedance at resonance is at maximum.

18.

In an RLC circuit, power loss can take place in

a)

R

b)

L

c)

C

d)

L and C

19.

Average power dissipated in an ideal inductor in a.c. circuit is:

a)

Infinite

b)

100

c)

0

d)

1

20.

The formula for inductive reactance is _____.

a)

XL = 1 ÷ 2πfL

b)

XL = 2 ÷ πfL

c)

XL = 2π ÷ fL

d)

XL = 2πfL

21.

A pure capacitor is connected to an AC power supply. In this circuit, the current

a)

leads the voltage by 90°.

b)

lags the voltage by 90°.

c)

is in phase with the voltage.

d)

none of the given answers

22.

What is the phase angle between the voltages of the inductor and capacitor in a RLC series circuit?

a)

zero

b)

90°

c)

180°

d)

270°

23.

Consider an RLC circuit that is driven by an AC applied voltage. At resonance,

a)

the peak voltage across the capacitor is greater than the peak voltage across the inductor.

b)

the peak voltage across the inductor is greater than the peak voltage across the capacitor.

c)

the current is in phase with the driving voltage.

d)

the peak voltage across the resistor is equal to the peak voltage across the inductor.

24.

What is alternating current

a)

the process of inducing an emf (voltage) with a change in magnetic flux

b)

Electric currents whose direction and magnitude change periodically depending on time are called alternating current

c)

Steady current which delivers the same average power as the a.c. to a resistive load.

d)

Making a rectified current more steady (or smooth) by placing a capacitor in parallel with the resistor

25.

Defines of the effective value of alternating current

a)

The process of inducing an emf (voltage) with a change in magnetic flux

b)

Electric currents whose direction and magnitude change periodically depending on time are called alternating current

c)

Steady current which delivers the same average power as the a.c. to a resistive load.

d)

Making a rectified current more steady (or smooth) by placing a capacitor in parallel with the resistor

26.

Electromagnetic Induction is ...

a)

The process of inducing an emf (voltage) with a change in magnetic flux

b)

Electric currents whose direction and magnitude change periodically depending on time are called alternating current

c)

Steady current which delivers the same average power as the a.c. to a resistive load.

d)

Making a rectified current more steady (or smooth) by placing a capacitor in parallel with the resistor

ALTERNATING CURRENT

Total questions: 26

Worksheet time: 14mins

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