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Worksheets18 Electromagnetic Induction 2023 IG
Total questions: 18
Worksheet time: 10mins
A teacher sets up the equipment for three demonstrations, P, Q and R.
In demonstration P, the magnet is moved to the right.
In demonstration Q, the switch is closed.
In demonstration R, the copper rod is moved vertically upwards.
Which demonstrations can be used to demonstrate electromagnetic induction?
P and Q only
P and R only
Q and R only
P, Q and R
A transformer in a computer is used to transform the mains voltage of 240 V to 12 V.
The number of turns on the secondary coil is 2000.
Which statement about the transformer is correct?
It is a step-down transformer and has 100 turns on its primary coil.
It is a step-down transformer and has 40 000 turns on its primary coil.
It is a step-up transformer and has 100 turns on its primary coil.
It is a step-up transformer and has 40 000 turns on its primary coil.
A transformer has Np turns on its primary coil and Ns turns on its secondary coil.
The voltage across the primary coil is Vp and the voltage across the secondary coil is Vs.
What is the relationship between these four quantities?
Vp × Vs = Np × Ns
Vp / Vs = Np / Ns
Vp / Vs = Ns / Np
Vp / Vs = Np × Ns
A generator uses the principle of electromagnetic induction. Which change would increase the induced electromotive force (e.m.f.) in the coil?
increasing the number of turns in the coil
placing the magnets further apart
using a coil made from steel wire
reversing one of the magnets
What is a transformer used for?
changing a direct current into an alternating current
changing the magnitude of an alternating voltage
reducing the frequency of an alternating current
switching off the current in a circuit when there is a fault
A current in a solenoid produces a uniform magnetic field inside the solenoid. The magnetic field direction is due east.
Which changes will produce a stronger magnetic field with a direction due west?
Use a smaller current and turn the solenoid through 180°.
Use a smaller current and reverse the current.
Use a larger current and turn the solenoid through 90°.
Use a larger current and reverse the current.
A transformer has Np turns on its primary coil and Ns turns on its secondary coil. The voltage across the primary coil is Vp and the voltage across the secondary coil is Vs. What is the relationship between these four quantities?
Vp × Vs = Np × Ns
Vp / Vs = Np / Ns
Vp / Vs = Ns / Np
Vp / Vs = Np × Ns
What is a transformer used for?
changing a direct current into an alternating current
changing the magnitude of an alternating voltage
reducing the frequency of an alternating current
switching off the current in a circuit when there is a fault
A simple electric generator induces an electromotive force (e.m.f.).
Which modification would increase the induced e.m.f.?
Increase the number of turns in the coil of the generator.
Increase the distance between the magnetic poles.
Reduce the strength of the magnetic field around the coil.
Reverse the direction of the magnetic field.
What is an advantage of transmitting electricity at a high voltage?
It is faster.
It is safer.
Less energy is wasted.
Less equipment is needed.
In which device is the magnetic effect of a current not used?
electromagnet
loudspeaker
potential divider
relay
The diagram represents the transmission of electricity from a power station to homes that are many kilometres away. Two transdormers are labelled X and Y.
What type of transformers are X and Y?
X: step-down transformer, Y: step-down transformer
X: step-down transformer, Y: step-up transformer
X: step-up transformer, Y: step-down transformer
X: step-up transformer, Y: step-up transformer
Which electrical device uses the turning effect produced by a current-carrying coil in a magnetic field?
a.c. generator
d.c. motor
relay
transformer
A student makes four different types of transformer.
She counts the number of turns on the primary and secondary coils.
She labels each transformer as either step-up or step-down. Which row shows the correct labels?
(a)
The diagram shows an a.c. generator.
The graph shows the potential difference (p.d.) between points X and Y plotted against time.
A positive value of p.d. indicates that X is more positive than Y. Which diagram shows the position of the coil at point P on the graph?
A step-down transformer is 100% efficient. It has an input voltage of 240 V a.c. and an output voltage of 60 V a.c. The current in the primary coil is 0.50 A.
What is the current in the secondary coil?
0.13 A
0.50 A
2.0 A
8.0 A
Which component forms part of a d.c. motor but not a simple moving coil a.c. generator?
the coil
the brushes
the magnet
the split-ring commutator
A transformer has 5500 turns on the primary coil and 500 turns on the secondary coil. The output of the secondary coil is 110 V a.c. and is connected to a heater. The transformer is 100% efficient. The heater produces a power of 132 W.
What is the current in the primary coil?
0.11 A
0.12 A
11 A
12 A
