Free Printable Week 9 Quiz EES102

1.

AC generators used to produce alternating current by converting

a)

kinetic energy into potential energy

b)

potential energy into electrical energy

c)

kinetic energy into electrical energy

d)

electrical energy into kinetic energy

2.

AC generators works based on

a)

Faraday's Law

b)

Lenz Law

c)

Newton's Law

d)

electrostatic law

3.

In AC generator, maximum emf generated at an angle of

a)

0 and 90

b)

90 and 180

c)

90 and 270

d)

180 and 360

4.

The distance of the waveform travel in one cycle is referred to

a)

amplitude

b)

wavelength

c)

time

d)

frequency

5.

The effective voltage value is

a)

25%

b)

50%

c)

71%

d)

90%

6.

The average current/ voltage value will not be zero only if it is

a)

step up

b)

rectified

c)

amplified

d)

intensified

7.

The resistor in an AC will cause

a)

no phase difference

b)

V lead I

c)

I lead V

d)

I lags V

8.

Voltage leads the current in an AC generators can be referred to

a)

resistance

b)

capacitance

c)

inductance

9.

The combination of resistance, capacitance and induntance is referred to

a)

impedance

b)

reactance

c)

angular frequency

d)

amplitude

10.

High potential voltage produced by three-phase generators commonly used in

a)

filament

b)

X-ray tube

c)

transformer

d)

anode

11.

All of the following have the same units except:

a)

inductance.

b)

capacitive reactance.

c)

impedance.

d)

resistance.

12.

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

13.

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.

14.

If the frequency of the AC voltage across an inductor is doubled, the inductive reactance of that inductor

a)

increases to 4 times its original value.

b)

increases to twice its original value.

c)

decreases to one-half its original value.

d)

decreases to one-fourth its original value.

15.

Quantity of charge can be measured in

a)

time (s)

b)

Ampere (A)

c)

coulombs (C)

d)

Joule (J)

16.

The function of a generator is to change ____.

a)

mechanical energy to electrical energy

b)

electrical energy to mechanical energy

c)

electrical energy to chemical energy

d)

chemical energy to electrical energy

17.

The formula for inductive reactance is

a)

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

b)

$\omega C$

c)

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

d)

$\omega L$

18.

A Capacitor blocks

a)

Only a.c.

b)

Only d.c.

c)

Both ac and dc

d)

None of these

19.

The instantaneous current in an ac circuit is i=2.0 sin314t, what is its frequency?

a)

100 Hz

b)

60 Hz

c)

50 Hz

d)

2π

20.

The instantaneous current in an ac circuit is i=2.0 sin314t, what is rms value of the current.

a)

1.414 A

b)

2.828A

c)

1 A

d)

2 A

21.

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

22.

An inductor of inductance 22.0 mH is connected to an a.c. supply with frequency f. If the reactance of the inductor is 660 Ω, what is the value of f?

a)

1.45 $\times10^3\$ Hz

b)

3.00undefined Hz

c)

4.77undefined Hz

d)

7.16undefined Hz

23.

The electricity in our house is

a)

AC

b)

DC

c)

BC

d)

AD

24.

What will happen, if we connect capacitor to DC Supply.

a)

It allows DC

b)

It blocks DC

c)

t rectifies

d)

None of these

e)

Hint: Diode is unidirectional and uncontrolled device. In rectifier circuit, diode use as a switch to convert ac to dc for rectification purpose.

25.

Which image shows the output of a sine-wave after it has gone through a diode? (Half-wave rectified)

a)

b)

c)

d)

26.

The induced emf in a closed coil of wire, according to Faraday’s Law, is proportional to:

I. The magnitude of the magnetic flux

II. The magnetic flux density

III. The number of turns

IV. The rate of change of magnetic flux

a)

I

b)

II

c)

II and III (

d)

III and IV

e)

IV

27.

A changing magnetic field B induces an emf Ɛ in a coil of radius R, as shown figure. What is the induced emf in the coil of radius 2R?

a)

Ɛ

b)

2 Ɛ

c)

4 Ɛ

d)

Ɛ/2

e)

Ɛ/4

28.

A uniform magnetic field is distributed in the space of a circle of radius r, as shown in figure. The changing field induces an emf Ɛ in the loop with radius r. What is the induced emf in the loop with radius 2r?

a)

Ɛ

b)

2 Ɛ

c)

4 Ɛ

d)

Ɛ/2

e)

Ɛ/4

29.

The number of turns in a long solenoid is doubled; how does the inductance of the solenoid change?

a)

It doesn’t change

b)

It doubles

c)

It quadruples

d)

It is cut to a half

e)

It is cut to a quarter

30.

Which of the following is true about an inductor?

I. It stores energy

after the current stops flowing

II. It opposes the

change of current

III. It can produce a

magnetic field

a)

I

b)

III

c)

I and II

d)

II and III

e)

All of the above

31.

Which of the following can act as an inductor?

I. A long coil

II. A long wire

III. A conducting sphere

a)

I

b)

III

c)

I and II

d)

II and III

e)

All of the above

32.

At time t = 0, the switch is closed. Which of the following graphs best describes the voltage V across the resistance R as a function of time t?

a)

b)

c)

d)

e)

33.

If L is inductance measured in H (Henry), what is 1 H equivalent to?

a)

1 Vs/A

b)

1 A/Vs

c)

1 AV/s

d)

1A∙s/V

e)

1 s/A V

34.

If R is 1 Ω and L is 1 H, then L/R is:

a)

1 V

b)

1 F

c)

1 A

d)

1 C

e)

1 s

35.

In the circuit given, what is the current at point P immediately after the switch is closed?

a)

Ɛ/R

b)

2Ɛ/R

c)

Ɛ/2R

d)

LƐ/R

e)

0

36.

In the circuit above, what is the current at point P after the switch is closed for a long time?

a)

Ɛ/R

b)

2Ɛ/R

c)

Ɛ/2R

d)

LƐ/R

e)

0

37.

The switch is closed for a long time in the circuit above; what is the energy stored in the inductor?

a)

LƐ/2R

b)

LƐ²/2R²

c)

LƐ²/2R

d)

LƐ/2R²

e)

0

38.

In the circuit above, the switch is initially open and then it is closed at time t = 0. What is the current in the resistor at this time?

a)

3 A

b)

1 A

c)

0

d)

0.5

e)

0.3

39.

In the circuit above, the switch has been closed for a long time, then it is reopened at time t = 0. Which of the following graphs best represents the electric current, i, as a function of time t?

a)

b)

c)

d)

e)

40.

In the circuit above, the switch is closed for a long time. What is the energy stored in the inductor?

a)

3 J

b)

6 J

c)

18 J

d)

0.5 A

e)

0.3 A

41.

An inductor of inductance of 0.4 H is connected in series to a resistor of 6 Ω and a 12 V battery. What is the energy stored in the inductor?

a)

0.8 J

b)

1.2 J

c)

1.8 J

d)

24 J

e)

36 J

42.

In the circuit above, at time t = 0, the switch is placed at position A. What is the current in the resistor at this time?

a)

0.3 A

b)

0.6 A

c)

0 A

d)

0.1 s

e)

0.6 s

43.

In the circuit above, the make before break switch has been kept at position A for a long time and then at time t = 0, is placed at position B. What is the current in the resistor at this time?

a)

0

b)

0.3 A

c)

0.6 A

d)

3 A

e)

6 A

44.

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)

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

45.

What happens at resonance?

a)

Current is maximum

b)

Impedance is maximum

c)

Resistance is maximum

d)

Power factor is maximum

46.

A pure resistor is connected to an a.c. source where its current is given by I=5.0 sin 628t. Which of the following statements is not true about the circuit?

a)

The peak value of current flowing through the resistor is 5.0 A

b)

The root mean square current flowing through the resistor is 3.5 A

c)

The frequency of the current flowing through across the resistor is 120 Hz

d)

The equivalent direct current which gives the same average heating power in the resistor is 3.5 A

47.

Find the ratio of $\frac{mean\ power\ dissipated\ through\ R\ in\ \left(a\right)}{power\ dissipated\ through\ R\ in\ \left(b\right)}$

a)

2

b)

$\frac{1}{2}$

c)

4

d)

$\frac{1}{4}$

48.

The variation of voltage across an inductor with time t in an a.c. circuit is as shown in the graph. Which graphs shows the variation of the current I which flows through the inductor with time t?

a)

b)

c)

d)

49.

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

50.

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

51.

Quantity of charge can be measured in

a)

time (s)

b)

Ampere (A)

c)

coulombs (C)

d)

Joule (J)

52.

The function of a generator is to change ____.

a)

mechanical energy to electrical energy

b)

electrical energy to mechanical energy

c)

electrical energy to chemical energy

d)

chemical energy to electrical energy

53.

An electric current that continually reverses direction over time is known as a(n)?

a)

Alternating current

b)

direct current

c)

simple current

54.

current is measured in?

a)

Volt

b)

ampere

c)

watt

55.

The electricity in our house is?

a)

AC

b)

BC

c)

DC

56.

the number of complete oscillations of the signal per unit time Is defined by?

a)

period

b)

peak current

c)

frequency

57.

A proton ( q = 1.60 x 10^-19 C) moves 10.0 cm on a path parallel to the direction of a uniform electrical field of strength 3.0 N/C. What is the electrical potential energy?

a)

4.8 x 10^-20 J

b)

1.6 x 10^-20 J

c)

-4.8 x 10^-20 J

d)

-1.6 x 10^-20J

58.

What will be the electrical potential at a distance of 0.15 m from a point charge of 6.0 µC? (k_c = 8.99 x 10⁹ N · m²/C²)

a)

5.4 x 10⁴ V

b)

3.6 x 10⁵ V

c)

2.4 x 10⁶ V

d)

1.2 x 10⁷ V

59.

The voltage across each bulb is 9V. What is the voltage across the cell?

a)

4.5

b)

9

c)

18

d)

27

60.

Electromotive force of a battery can be defined with the formula of

a)

E = IR

b)

E = IR + I

c)

E = IR + r

d)

E = IR + Ir

Week 9 Quiz EES102

Total questions: 60

Worksheet time: 30mins

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