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WorksheetsElectrical Science and principles
Total questions: 44
Worksheet time: 1hrs 27mins
The SI unit of mass is the:
kilogram or kg
pound or lb
metre or m
millimetre or mm
The SI unit of electrical charge is the:
ohm
joule
watt
coulomb
Area is represented by:
kg
m²
m³
m
A shower unit draws 20 A from a domestic 230 V supply. Calculate the amount of power used.
4.6kW
11.5kW
46kW
0.08kW
Rearrange the formula R = p L/A to find p.
p = R/LA
p = RA/L
p = RL/A
p = A/RL
A 12 Ω filament lamp was found to be taking a current of 2 A at full brilliance. The voltage across the lamp under these conditions is:
6V
12V
24V
48V
The resistance of a kettle element which takes 12 A from a 230 V mains supply is:
2.88 Ω
5.00 Ω
12.24 Ω
19.16 Ω
Calculate the energy generated when a circuit is supplied with 100 V, and a current of 2 amperes flows for 6 minutes.
72 KJ
1.2 KJ
12 KJ
7000 J
Domestic wiring uses what kind of insulation material?
Mica
PVC
Mineral oxide
Glass
Good insulator materials include:
Copper
PVC
mica
mineral oxide
230 V is a measure of:
potential difference
amps
watts
ohms
An electron:
is negatively charged
is positively charged
has no charge
is balanced
A good conductor material:
has lots of free electrons
has no free electrons
may be made of copper
may be made of plastic
A good insulator material:
has lots of free electrons
has few free electrons
may be made of copper
may be made of plastic
Which of the following would be considered loads:
motor
lamp
circuit breaker
switch
Which of the following uses steam to generate electricity?
Oil
Solar thermal
Coal
Nuclear
A large industrial outlet needs which of the following supplies?
400 V three phase and neutral
400 V single phase
230 V single phase
230 V three phase and neutral
Alternating current is used in the distribution and transmission of electricity because: transformers only work with a.c.
it is cheaper than d.c.
transformers do not work on d.c.
transformers only work with a.c.
it is safer than d.c
If a person has a stream flowing through their land, which of the following could they take advantage of?
Micro-hydro
Micro-turbine
Air source ground pump
Ground source ground source
Micro-generation technology:
can reduce the effect of changes in energy prices to households
can increase the effect of changes in energy prices to households
can reduce the emission of carbon dioxide
is extremely inefficient
Which of the following uses the energy from the sun in order to produce hot water?
Ground source heat pump
Air source heat pump
Solar thermal
Photovoltaic
A 20V battery causes 2 amps of current to flow in a circuit when two resistors R1 & R2 are connected to it. The resistors are connected in series with R1 being valued at 8 Ω. Work out the value of R2.
20 Ω
12 Ω
5 Ω
2 Ω
Resistors of 6 Ω and 3 Ω are connected in series. The combined resistance value will be:
2.0 Ω
3.6 Ω
6.3 Ω
9.0 Ω
Three resistors, each valued at 6Ω, are connected in parallel. Work out the total resistance.
a. 3 Ω
b. 6 Ω
c. 18 Ω
d. 2 Ω
3 Ω
6 Ω
18 Ω
2 Ω
Resistors of 60 Ω, 40 Ω, and 20 Ω are connected in parallel. The total resistance value will be:
10.9 Ω
20.04 Ω
60.0 Ω
120 Ω
Lines of magnetic field flow from:
north to north
south to south
north to south
south to north
An electromagnetic device which controls a large electrical supply by switching a smaller powered circuit is known as:
a transformer
a diode
a relay
an inductor
An electromagnetic device which uses a solenoid to operate a number of contacts is one definition of:
a transformer
a motor
a relay
an inductive coil
Fleming’s right hand rule is associated with:
a generator
a motor
a relay
an inductor
The principle of electrical transmission is:
voltage is high, current is low, conductors are small, more efficient due to less heat loss
voltage is low, current is high, conductors are small, more efficient due to less heat loss
voltage is high, current is low, conductors are large, more efficient due to less heat loss
voltage is high, current is low, conductors are small, more efficient due to more heat loss
Who defined the formula Force = Mass x acceleration?
Fahrenheit
Newton
Bell
Watt
Which of the following may be defined as ‘the capacity for doing work’?
Energy
Work done
Power
Velocity
Which of the following may be defined as 'the speed in a given direction'?
Acceleration
Work done
Power
Velocity
Which of the following may be defined as ‘the rate of doing work’?
Acceleration
Work done
Power
Velocity
In a three-phase system, what is the function of the neutral cable?
Produces 230 V
Carries unbalanced currents
Produces 400 V
Carries balanced currents
Which configuration gives us two values of voltage?
Star
Delta
Star two-phase
Delta four-wire
Measuring across two lines of a star-connected three-phase four-wire supply system from the local substation would have a voltage of:
230 V
400 V
25 kV
132 kV
The phase voltage of a star-connected load is 100 V. The line voltage will be:
57.73 V
100 V
173.2 V
230 V
One application for a single phase induction motor is:
an electric train
a microwave oven
a central heating pump
an electric hand drill
Fleming’s left hand rule is associated with:
a generator
a motor
a relay
an inductor
A transformer is associated with:
self-induction
electromagnetism
magnetic induction
mutual induction
If a transformer has no losses, what does this mean?
power in equals power out
power in is less than power out
power out is less than power in
power out is double power in
A safety isolation transformer?
requires earthing
does not require earthing
is used with shaver sockets
only has one winding
A safety isolation transformer?
requires earthing
does not require earthing
is used with shaver sockets
only has one winding
