Worksheets5357 103 Written
Total questions: 24
Worksheet time: 12mins
Name
Class
Date
1.
Electricity is generated at which voltage?
a)
133kV
b)
400kV
c)
25kV
d)
33kV
2.
Which of these is a transmission voltage?
a)
66kV
b)
33kV
c)
25kV
d)
133kV
3.
Which of these is not a method for cooling transformers?
a)
Air
b)
Oil
c)
Gas (Sf6)
d)
Refrigeration
4.
Which of these does not contribute to transformer core losses?
a)
Hysteresis
b)
Eddy currents
c)
Type of core (Core/Shell)
d)
Copper losses
5.
Back EMF in a winding is caused by?
a)
Fluctuations in resistance
b)
Fluctuations in voltage
c)
Fluctuations in current
d)
Fluctuations in magnetic fields
6.
Inductive reactance is represented by?
a)
X
b)
XC
c)
XL
d)
X0
7.
If XL=60Ω and R=80Ω calculate Z?
a)
110Ω
b)
105Ω
c)
115Ω
d)
100Ω
8.
A 15kW motor has a power factor of 0.83. What is the value of the apparent power?
a)
17kVA
b)
18kVA
c)
19kVA
d)
20kVA
9.
The consumers installation begins where?
a)
Outgoing terminals of the cutout
b)
Incoming terminals of the meter
c)
Incoming terminals of the consumer unit
d)
Outgoing terminals of the meter
10.
What is the max size fuse now fitted in a domestic cutout?
a)
80A
b)
40A
c)
100A
d)
60A
11.
A 2.8kW motor drawing 16A from a 230V supply would have a power factor of?
a)
0.87
b)
0.76
c)
0.68
d)
0.67
12.
Where would a capacitor be fitted for power factor correction?
a)
In series with the load
b)
In parallel with the supply
c)
In line only
d)
in neutral only
13.
What would happen if the capacitor was removed from a fluorescent light?
a)
It would stop working
b)
It would flicker
c)
It would draw less current
d)
It would draw more current
14.
In a 3 phase star system with a 30Ω load on each phase IL=?
a)
6.7A
b)
6.9kA
c)
2.5A
d)
7.6A
15.
A high starting torque is a characteristic of which DC motor?
a)
Compound
b)
Series
c)
Shunt
d)
Parallel
16.
Having a smaller diameter wire in the start winding of a induction start single phase motor gives it a?
a)
Lower resistance & a capacitive effect
b)
Higher resistance causing phase displacement
c)
Magnetic resonance
d)
Higher voltage
17.
3 phase induction motors are?
a)
Heavier and difficult to move
b)
Smaller and cheaper to maintain
c)
Noisier and dangerous
d)
No different to single phase ones
18.
Under voltage protection is achieved in a contactor by the?
a)
The stop button
b)
The contactor coil
c)
The hold-on contact
d)
The overload coil
19.
What in a RCD disconnects the supply in the event of a fault?
a)
Test button
b)
Toroidal core
c)
Trip coil
d)
The load
20.
If a lamp emitting 7000 cd is suspended 9m above the floor what is the illuminance directly below?
a)
86 lux
b)
777 lux
c)
172 lux
d)
43 lux
21.
What type of lamp would be best suited for a car head light?
a)
Low pressure mecury
b)
High pressure sodium
c)
High pressure mercury
d)
Metal Halide
22.
In a tungsten halogen lamp what happens to the tungsten when the light is turned off?
a)
It settles on the surface of the glass
b)
It settles on the surface of the quartz
c)
It settles in the bottom of the lamp
d)
It settles back on the element
23.
Which of these is not a method of heating?
a)
Convection
b)
Conduction
c)
Vibration
d)
Radiation
24.
Storage heaters store heat in?
a)
Pipes
b)
Metal bars
c)
Bricks
d)
Insulation
100 %
