Free Printable EE 311 - MIDTERM EXAM

1.

What are the set of rules or practices intended for a safe execution of work?

a)

Rules and Regulation

b)

Policy Order

c)

Safety Practices

d)

Action Plan

2.

Which component resists the flow of current in an electrical circuit?

a)

Capacitor

b)

Resistor

c)

Inductor

d)

Transistor

3.

A two-terminal electronic component that conducts current primarily in one direction.

a)

Resistor

b)

Capacitor

c)

Diode

d)

Transistor

4.

A device that regulates current or voltage flow and acts as a switch and can amplify electronic signals.

a)

Resistor

b)

Capacitor

c)

Diode

d)

Transistor

5.

It is used to increase or decrease the voltage in electrical line.

a)

Fuse

b)

Transformer

c)

Switch

d)

Transistor

6.

An electrical component that can make or break an electrical circuit.

a)

Transformer

b)

Switch

c)

Fuse

d)

Transistor

7.

A conductive pattern formed on one or both sides of an insulation bass by etching, plating or stamping.

a)

Printed Circuit Board

b)

Plate

c)

Breadboard

d)

VOM

8.

A diagram that shows the graphical symbols, electrical connections and the functions of the different parts of a circuit.

a)

Schematic Diagram

b)

Layout

c)

Block Diagram

d)

Pictorial Diagram

9.

Which is not function of VOM?

a)

Voltmeter

b)

Ohmmeter

c)

Millimeter

d)

Milliammeter

10.

What unit of measurement are Power Supplies measured in?

a)

Joules

b)

Gigahertz

c)

Watts

d)

Gigabytes

11.

Why does the technician opening up the PSU touch the heatsinks with the screwdriver first?

a)

to eliminate static charge

b)

to make sure they are not hot

c)

for good luck

d)

to disable the PSU

12.

What is the purpose of a Power Supply?

a)

Converts AC power to lower voltage DC Power

b)

Creates power for a computer

c)

Stores data

d)

Convert AC power to a higher voltage DC power

13.

Which one is not a common voltage supplied by a power supply?

a)

3.3

b)

500

c)

5

d)

12

14.

What type of power connector is this?

a)

SATA

b)

SCSI

c)

Molex

d)

Berg

15.

A 5 volt power wire that is providing power to the motherboard would be what color?

a)

Yellow

b)

Blue

c)

Orange

d)

Red

16.

Even after the forward current reduces to zero value, a practical diode continues to conduct in the reverse direction for a while due to the

a)

stored charges in the depletion region

b)

high junction temperature

c)

none of the above

17.

When the p-n junction diode is reversed biased, the width of the depletion region __________

a)

Remains Constant

b)

Increases

c)

Decreases

18.

Which of the below mentioned statements is false regarding a p-n junction diode?

a)

Diode are uncontrolled devices

b)

Diodes are rectifying devices

c)

Diodes are unidirectional devices

d)

Diodes have three terminals

19.

1. An ideal diode has _________ &__________

a)

Some forward voltage drop, some reverse recovery time

b)

High switching losses, high reverse voltage drop

c)

No forward voltage drop, negligible reverse recovery time

d)

No reverse recovery time, high leakage current

20.

As the switch (shown in the green) is pressed, the voltage across the diode(ideally)

a)

Increases to Vs/R

b)

Increases to Vs

c)

Decreases to zero

d)

Remains Constant

21.

POWER ELECTRONICS is ---------------------

a)

The study of a continuously variable signal

b)

The study of digital signals and the engineering of devices

c)

The study of technology concerned with the combined use of electronics and light.

d)

The study of Switching electronic circuits in order to control the flow of electrical energy.

22.

What is the role of power electronics in the industry ?

a)

electric and hybrid vehicles

b)

Renewable energy systems

c)

bulk utility energy storage

d)

ALL THE ABOVE

e)

NONE OF THE ABOVE

23.

In power electronics the power Loss is __________

a)

Less

b)

High

c)

moderate

24.

Even after the forward current reduces to zero value, a practical diode continues to conduct in the reverse direction for a while due to the

a)

stored charges in the depletion region

b)

high junction temperature

c)

none of the above

25.

Surrounding every magnet is a __________ __________.

a)

magnetic field

b)

electrical current

c)

another magnet

d)

an enemy

26.

What two forces are required for generators and electric motors to work?

a)

magnetism and thermal

b)

electricity and thermal

c)

electricity and magnetism

d)

magnetism and radiant

27.

Generators are devices that convert _____ energy into _____ energy.

a)

chemical; mechanical

b)

mechanical; electrical

c)

electrical; mechanical

d)

potential; kinetic

28.

What can you use to make an electromagnet?

a)

Battery, nail and string

b)

Battery, pencil and wire

c)

Wire, battery and iron ore (nail)

d)

Peanut butter, lampshade, hand sanitizer

29.

Electric fields are often associated with what other kind of field?

a)

Magnetic Fields

b)

Nuclear Fields

c)

Particle Fields

d)

Corn Fields

30.

What device is made of coils of wire with an electrical current passing through it in order to generate a magnetic field?

a)

Electromagnet

b)

Generator

c)

Electron Magnet

d)

Motor

31.

What is the transfer of energy in when you plug in a motor and it spins?

a)

chemical to mechanical

b)

electrical to mechanical

c)

mechanical to electrical

d)

physical to potential

32.

What can you do to make electromagnets stronger?

a)

Increase number of coils of wire.

b)

Increase number of batteries used.

c)

Both A and B.

d)

Neither A nor B.

33.

This picture shows a turbine generator used to produce electricity at a geothermal power plant.
Electricity is produced by using steam to _____________.

a)

heat the turbine generators

b)

spin the turbine generators

c)

reduce friction in the turbine generators

d)

reduce emissions from the turbine generators

34.

In an electric motor, the energy transformation begins as ----

a)

electrical and becomes chemical

b)

mechanical and becomes electrical

c)

electrical and becomes mechanical

d)

mechanical and becomes chemical

35.

A motor converts electrical current into

a)

chemical energy

b)

chemical force

c)

mechanical force

d)

mechanical life

36.

electric generators converts mechanical force into

a)

mechanical energy

b)

magmatism

c)

electric current

d)

electric energy

37.

Which best describes how a motor works?

a)

When a fan blows on a wire, it causes it to spin, creating a force.

b)

When a fan blows on a wire, it causes it to spin, creating an electrical current.

c)

When a wire that carries electrical current is placed in zero gravity, the wire experiences a force.

d)

When a wire that carries electrical current is placed in a magnetic field, the wire experiences a force.

38.

Which statement best explains the flow of energy through a motor?

a)

battery-->electrical current-->copper wire rotor -->magnet--> mechanical energy

b)

battery--> magnet--> electrical current--> copper wire rotor--> mechanical energy

c)

magnet--> mechanical energy--> copper wire rotor--> battery--> electrical current

d)

magnet--> copper wire rotor--> mechanical energy--> battery--> electrical current

39.

Which of the following are true for motors? Select all that apply.

a)

Motors transform electrical energy into mechanical energy.

b)

Motors contain an electromagnet that spins between a permanent magnet.

c)

Motors transform chemical energy into electrical energy.

d)

A motor spins due to the attraction and repulsion of magnets.

40.

An electric field is created by particles that

a)

are moving.

b)

have a charge.

c)

are radioactive.

d)

are electrically neutral.

41.

When arc welding do not use cables that are

a)

welded

b)

soldered

c)

cracked, cut, frayed

d)

spliced

42.

What type of welding requires the use of an electrode in the form of wire spools?

a)

Stick

b)

MIG

c)

TIG

d)

OxyAcetylene

43.

What type of welding can cut through metal with the help of oxygen?

a)

MIG

b)

TIG

c)

OxyAcetylene

d)

Stick

44.

What type of welding does not require electrical power?

a)

MIG

b)

OxyAcetylene

c)

TIG

d)

Stick

45.

What type of welding does not use a gas for the process?

a)

OxyAcetylene

b)

MIG

c)

TIG

d)

Stick

46.

Saturation of clothing by moisture or perspiration increases the risk of

a)

weld burns

b)

electrical shock

c)

welder fatigue

d)

getting a flash

47.

Hot metal should be handled with

a)

gloves

b)

aprons

c)

tongs or pliers

d)

rag

48.

When starting to arc weld, the operator should

a)

turn on the exhaust fan

b)

clean area of scraps and tools

c)

shield others from arc rays

d)

all of these

49.

The welding are should be kept free from which of the following ?

a)

grease, fuels, & solvents

b)

Ultraviolet Rays

c)

Electrodes

d)

Infrared Rays

50.

The welding are should be kept free from which of the following ?

a)

grease, fuels, & solvents

b)

Ultraviolet Rays

c)

Electrodes

d)

Infrared Rays

51.

Arc welding can produce _________that can damage your eyes.

a)

Ultra Violet Light

b)

Gases

c)

Noise

d)

Heat

52.

Which type of gloves should be wore when arc welding?

a)

Gauntlet Style Gloves

b)

Work Gloves

c)

Cotton Gloves

d)

Synthetic Gloves

53.

When welding the operator should never stand in/on_________.

a)

Concrete

b)

Damp Ground

c)

Metal

d)

Wood structures

54.

In purely capacitor circuit

a)

Voltage lead current by 180 degree

b)

Voltage lag current by 180 degree

c)

Current lag voltage by 90 degree

d)

Current lead voltage by 90 degree

55.

In pure resistance single phase circuit

a)

Voltage and current are same

b)

voltage and current are in same phase

56.

Average power in single phase AC circuit is zero. This means circuit is

a)

series RLC circuit

b)

parallel RLC circuit

c)

pure inductive circuit

d)

pure resistance circuit

57.

if $v=V_{0_{\ }}Sin\ \left(314t+13^0\right)$ , the voltage in polar form will be

a)

$\frac{V}{\sqrt{2}}\angle13^0$

b)

$\frac{V_0}{\sqrt{2}}\angle13^0$

c)

$V_0\angle13^0$

d)

$v\angle13^0$

58.

For a single phase 25 Hz ac system, supply voltage is $100\angle25^0$ . the equivalent sinusoidal volatge is

a)

$v=141.4\sin\left(314t+25^0\right)$

b)

$v=100\sin\left(157t+25^0\right)$

c)

$v=141.4\sin\left(157t+25^0\right)$

d)

$v=100\sin\left(314t+25^0\right)$

59.

For a series R-L circuit having inductive reactance 3 ohm and resistance $\sqrt{3}$ . The power factor will be

a)

0.5

b)

1

c)

0

d)

$\sqrt{3}$

60.

The power factor is defined as

a)

cosine of the phase difference between voltage and current

b)

ratio of resistance with impedance

c)

ratio of active power with apparent power

d)

All of above

61.

power factor is 0.95 lagging indicates

a)

Current lags to voltage by $\cos^{-1}\left(0.95\right)$

b)

Voltage lags to current by $\cos^{-1}\left(0.95\right)$

c)

any one may correct

d)

both are correct

62.

1. Voltage in sinusoidal form is $v=230\sin\left(314t+46^0\right)$ . The value after converting into rectangular form is

a)

110.06+j115.41

b)

112.98+j116.99

c)

112.98-j116.99

d)

116.99+j112.98

63.

If 0.5 ohm resistance 10 mili Henry inductance and 1000 micro Farad are connected in series with 50 Hz single phase AC supply. The load power factor will be

a)

0.99

b)

0.999

c)

0.996

d)

0.991

64.

if $v=25\sqrt{2}\sin\left(157t-10\right)$ and $i=2\sqrt{2}\sin\left(157t+40\right)$ , the true power is

a)

$25\times2\times\cos\left(40+10\right)$

b)

$25\times2\times COS\left(40-10\right)$

c)

$25\sqrt{2}\times2\sqrt{2}\times\cos\left(-10-40\right)$

d)

$25\sqrt{2}\times2\sqrt{2}\times\cos\left(-10+40\right)$

65.

Active power is also named as,

a)

Real power

b)

True power

c)

kW power

d)

All of the above

e)

None of these

66.

power factor is defined as

a)

$\frac{impedance}{resis\tan ce\ }$

b)

$\frac{active\ power}{reactive\ power}$

c)

$\frac{kW}{kVA}$

d)

cosine of the angle of current

67.

$v=40\angle60^0\$ voltage is connected across series R and L. A current $i=10\angle30^0$ is flowing in the circuit. Assuming 50 Hz single phase AC supply, the value of R and L will be

a)

3.464 ohm and 6.37 mH

b)

3.56 ohm and 9.37 mH

c)

3.464 ohm and 6 mH

d)

3.464 ohm and 16.37 mH

68.

$if\ z1=5+j25\ ohm\ z2=20\angle60\ ohm\$ are connected in parallel. the net impedance would be

a)

$11.36\angle68.21^0$ ohm

b)

$4.22+j10.55$ ohm

c)

both are correct

d)

none of these

69.

A polyphase system is generated by_____

a)

Having two or more generator windings separated by equal electrical angle.

b)

Having generator windings at equal distances

c)

None of the above

d)

A and C

70.

In a three phase AC circuit, the sum of all three generated voltages is ______

a)

Infinite (∞)

b)

Zero (0)

c)

One (1)

d)

none of the above

71.

In a three phase, delta connection ——-

a)

line current is equal to phase current

b)

Line voltage is equal to phase voltage

c)

None of the above

d)

Line voltage and line current is zero

72.

In a Y-connected circuit, the magnitude of each line current is

a)

line current is equal to phase current

b)

Line voltage is equal to phase voltage

c)

None of the above

d)

Line voltage and line current is zero

73.

In a certain three-wire Y-connected generator, the phase voltages are 2 kV. The magnitudes of the line voltages are

a)

2,000 V

b)

6,000 V

c)

666 V

d)

3,464 V

74.

If in a Y-connected ac generator, each phase voltage has a magnitude of 90 VRMS, what is the magnitude of each line voltage?

a)

0 V

b)

90 V

c)

156 V

d)

180 V

75.

The use of inductor?

a)

Passive component that store food in a fridge when electric current flows through it.

b)

Passive component that store energy in a magnetic field when electric current flow through it

c)

Passive component that store electric charge in an AC circuit.

d)

Passive component that limit the current flow.

EE 311 - MIDTERM EXAM

Total questions: 75

Worksheet time: 30mins

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