Deck 2: Understand the Fundamental Principles and Requirements of Environmental Technology Systems

Question 1

One application for a series d.c. motor is:

A) an electric train
B) a microwave oven
C) a central heating pump
D) an electric drill.

Answer 1

an electric train
an electric drill.

Question 2

An a.c. series circuit has a capacitive reactance of 12 ? and a resistance of 9 ?. The impedance of this current will be:

A) 3 ?
B) 15 ?
C) 20 ?
D) 108 ?.

Answer 2

15 ?

Question 3

An a.c. series circuit has an inductive reactance of 4 ? and a resistance of 3 ?. The impedance of this circuit will be:

A) 5 ?
B) 7 ?
C) 12 ?
D) 25 ?.

Answer 3

5 ?

Question 4

A straight line having definite length and direction that represents to scale a quantity such as current voltage or impedance is called:

A) a series a.c. circuit
B) capacitive reactance
C) a phasor, as in a phasor diagram
D) the impedance triangle.

Question 5

The total opposition to current fl ow in any a.c. circuit is called:

A) resistance
B) inductance
C) reactance
D) impedance.

Question 6

The opposition to current flow in an a.c. capacitive or inductive current is called:

A) resistance
B) inductance
C) reactance
D) impedance.

Question 7

The opposition to current flow in an a.c. resistive circuit is called:

A) resistance
B) inductance
C) reactance
D) impedance.

Question 8

Two identical resistors are connected in parallel across a 24 V battery. The voltage drop across each resistor will be:

A) 24 V.
B) 2 V
C) 6 V
D) 12 V

Question 9

Two identical resistors are connected in series across a 24 V battery. The voltage drop across each resistor will be:

A) 2 V
B) 6 V
C) 12 V
D) 24 V.

Question 10

The inductive reactance of a 100 mH coil when connected to a 50 Hz supply will be:

A) 5 ?
B) 20 ?
C) 31.42 ?
D) 31.42 k?.

Question 11

The capacitive reactance of a 100 ?F capacitor when connected to a 50 Hz supply will be:

A) 5 ?
B) 20 ?
C) 31.8 ?
D) 31.8 k?.

Question 12

A circuit with bad power factor causes:

A) a fall in the supply voltage
B) an increase in the supply voltage
C) more current to be taken from the supply
D) less current to be taken from the supply.

Question 13

A good insulator material:

A) has lots of free electrons
B) has no free electrons
C) may be made of copper
D) may be made of plastic.

Question 14

A good conductor material:

A) has lots of free electrons
B) has no free electrons
C) may be made of copper
D) may be made of plastic.

Question 15

Good insulator materials are:

A) copper
B) PVC
C) brass
D) wood.

Question 16

Good conductor materials are:

A) copper
B) PVC
C) brass
D) wood.

Question 17

An electromagnetic switch operated by a solenoid is one definition of:

A) a transformer
B) an a.c. motor
C) a relay
D) an inductive coil.

Question 18

A step down transformer has 1000 turns on the primary winding and 500 turns on the secondary winding. If the input voltage was 230 V the output voltage will be:

A) 2 V
B) 115 V
C) 200 V
D) 460 V.

Question 19

One application for a shaded pole a.c. motor is:

A) an electric train
B) a microwave oven
C) a central heating pump
D) an electric drill.

Question 20

One application for an a.c. induction motor is:

A) an electric train
B) a microwave oven
C) a central heating pump
D) an electric drill.

Question 21

Resistors of 20 ?, 40 ? and 60 ? are connected in parallel. The total resistance value will be:

A) 10.9 ?
B) 20.0 ?
C) 60.0 ?
D) 120 ?.

Question 22

Resistors of 60 ?, 40 ? and 20 ? are connected in series. The total resistance value will be:

A) 10.9 ?
B) 20.0 ?
C) 60.6 ?
D) 120 ?.

Question 23

Resistors of 6 ? and 3 ? are connected in parallel. The combined resistance value will be:

A) 2.0 ?
B) 3.6 ?
C) 6.3 ?
D) 9.0 ?.

Question 24

The newton is a measure of:

A) potential difference
B) power
C) force
D) electric current.

Question 25

The SI unit of resistance is the:

A) ohm or ?
B) volt or V
C) watt or W
D) ampere or A.

Question 26

The SI unit of electric current is the:

A) ohm or ?
B) volt or V
C) watt or W
D) ampere or A.

Question 27

The SI unit of length is the:

A) kilogram or kg
B) pound or lb
C) metre or m
D) millimetre or mm.

Question 28

Which of the following may be defined as 'a measure of the force which a body exerts on anything which supports it':

A) acceleration
B) force
C) mass
D) weight.

Question 29

Which of the following may be defined as 'a measure of the amount of material in a substance':

A) acceleration
B) force
C) mass
D) weight.

Question 30

Which of the following may be defined as 'may cause a stationary object to move or bring a moving body to rest':

A) acceleration
B) force
C) mass
D) weight.

Question 31

Resistors of 6 ? and 3 ? are connected in series. The combined resistance value will be:

A) 2.0 ?
B) 3.6 ?
C) 6.3 ?
D) 9.0 ?.

Question 32

Current flowing through a solenoid sets up a magnetic flux. If an iron core is added to the solenoid while the current is maintained at a constant value, the magnetic flux will:

A) remain constant
B) totally collapse
C) decrease in strength
D) increase in strength.

Question 33

A 12 ? filament lamp was found to be taking a current of 2 A at full brilliance. The voltage across the lamp under these conditions is:

A) 6 V
B) 12 V
C) 24 V
D) 48 V.

Question 34

The resistance of a kettle element which takes 12 A from a 230 A main supply is:

A) 2.88 ?
B) 5.00 ?
C) 12.24 ?
D) 19.16 ?.

Question 35

The current taken by a 10 ? resistor when connected to a 230 V supply will be:

A) 2.3 A
B) 10 A
C) 23 A
D) 230 A.

Question 36

Which of the following may be defined as 'the speed in a given direction':

A) acceleration
B) work done
C) power
D) velocity

Question 37

Which of the following may be defined as 'the rate of doing work':

A) acceleration
B) work done
C) power
D) velocity

Question 38

Which of the following may be defined as 'the force applied times the distance moved in the direction of the force':

A) acceleration
B) work done
C) power
D) velocity

Question 39

The SI unit of mass is the:

A) kilogram or kg
B) pound or lb
C) metre or m
D) millimetre or mm.