Which diagram shows the correct magnetic field pattern around a current-carrying solenoid?
Did this page help you?
Which diagram shows the correct magnetic field pattern around a current-carrying solenoid?
Did this page help you?
Which diagram correctly shows the magnetic field lines around a current-carrying wire if the current is directed out of the page?
Did this page help you?
Extended tier only
Which device uses a split ring commutator?
d.c. motor
transformer
relay
a.c. generator
Did this page help you?
A simple d.c. electric motor is shown in the diagram.
Which of the following changes would make the coil turn more quickly?
Reducing the strength of the magnetic field.
Reversing the direction of the current and swapping the magnetic poles.
Swapping the magnetic poles.
Increasing the current in the coil
Did this page help you?
The number of turns in the primary coil and secondary coil of a transformer is Np and Ns respectively.
Which of the following statements represents a step-up transformer?
Did this page help you?
After electricity is generated at a power station, the voltage is increased significantly for transmission across the country via the national grid.
What is the advantage of transmitting electricity at very high voltages?
It makes the electricity flow more quickly.
It increases the efficiency of the electricity transfer.
It produces more power.
It is safer to transmit electricity at high voltage.
Did this page help you?
When a wire is moved through a magnetic field, an e.m.f. is induced in the wire.
Which of the following devices uses this effect?
electric motor
electricity generator
photon accelerator
transformer
Did this page help you?
Extended tier only
Beta and gamma radiation are passed through two metal plates, with equal and opposite charges, as shown in the diagram below.
Which direction, if any, would the β-particles and γ-rays be deflected?
| β-particles | γ-rays |
A | into the page | continue straight |
B | towards the negative plate | out of the page |
C | continue straight | towards the negative plate |
D | towards the positive plate | continue straight |
Did this page help you?
Extended tier only
Which graph represents the output of a simple a.c. generator?
Did this page help you?
Transformers are used to change the voltage of a power supply.
The diagram below shows a simple transformer.
If the input voltage is 48 V, what is the output voltage?
2.4 V
9.6 V
240 V
667 V
Did this page help you?
Extended tier only
A magnetic field can be represented by the diagram shown below. The dots represent magnetic field lines coming out of the page.
A beam of alpha particles is directed through the field as shown above. Alpha particles, being charged, will be deflected by the field.
In which direction will the alpha particles be deflected?
upwards
downwards
into the page
out of the page
Did this page help you?
Extended tier only
The south pole of a magnet is brought near to a solenoid, which is connected to an ammeter. The magnet is then pulled away again.
As the magnet is moved towards point P the needle on the ammeter deflects. When it is moved away from point P, the needle on the ammeter also deflects.
What magnetic pole is produced at P when the south pole of the magnet is brought towards and away from the solenoid?
| S pole brought towards P | S pole moved away from P |
A | N | N |
B | N | S |
C | S | N |
D | S | S |
Did this page help you?
Extended tier only
A current-carrying wire is placed between two magnetic poles as shown in the diagram below. It experiences an upwards force.
What is the orientation of the magnetic poles?
| Left magnet | Right magnet |
A | N | N |
B | S | N |
C | N | S |
D | S | S |
Did this page help you?
Extended tier only
A transformer is used to raise the voltage of electricity produced at a power station before it is transmitted in power lines.
The power station generates electricity at a voltage of 25 kV and a current of 4000 A. The step-up transformer increases the voltage to 400 kV.
Assume that the transformer is 100% efficient.
What current flows in the power lines?
0.25 A
250 A
640 A
64 000 A
Did this page help you?
A transformer has 1200 turns on its secondary coil and has an output voltage of 240 V.
If the input voltage is 12 V, how many turns are there on the primary coil?
2
60
1200
24 000
Did this page help you?
Extended tier only
A current-carrying wire is placed into a magnetic field as shown in the diagram. The wire experiences a force.
In which direction does the force on the wire act?
OP
PO
ST
QR
Did this page help you?