Define Law of Magnetism .

The Law of Magnetism states that two like poles repel each other and two unlike poles attract each other. The attraction and repulsion between magnetic poles are examples of non-contact forces .

True or False? All metals are magnetic materials.

False. Only a few metals are magnetic materials : iron , cobalt , nickel , and steel (an alloy containing iron). Metals such as copper , gold , and aluminium are not magnetic.

Define induced magnet .

An induced magnet is a magnetic material that temporarily becomes a magnet when placed in a magnetic field . It loses most or all of its magnetism quickly when removed from the field.

How can you test whether a material is a magnet or just a magnetic material ?

Bring the material close to a known magnet. If it can be repelled , it is itself a magnet . If it can only be attracted and never repelled, it is a magnetic material (not a magnet).

A permanent magnet is made from a material such as .......... and produces its own .......... field without losing its magnetism.

A permanent magnet is made from a material such as steel and produces its own magnetic field without losing its magnetism.

When a magnetic material is brought close to a permanent magnet, which pole does the near end of the material develop?

The end of the magnetic material closest to the magnet develops the opposite pole to the magnet's nearest pole. This is why magnetic materials are always attracted to magnets.

True or False? The poles of a magnet are called positive and negative.

False. The poles of a magnet are called North and South — not positive and negative (those terms apply to electrical charge , not magnetism).

List the four magnetic materials.

The four magnetic materials are: Iron Cobalt Nickel Steel (an alloy of iron)

Define magnetic field .

A magnetic field is the region around a magnet where a force acts on another magnet or on a magnetic material ( iron , steel , cobalt , and nickel ). The field is strongest at the poles of the magnet.

In what direction do magnetic field lines always point around a bar magnet?

Magnetic field lines always point from the north pole to the south pole of a magnet. This direction is shown by an arrow midway along each line.

The strength of a magnetic field is shown by the .......... of the field lines: field lines .......... together indicate a stronger field.

The strength of a magnetic field is shown by the spacing of the field lines: field lines closer together indicate a stronger field.

Define uniform magnetic field .

A uniform magnetic field has the same strength and direction at all points. It is represented by parallel, equally spaced field lines with arrows all pointing in the same direction. It is produced between opposite poles held close together.

True or False? Magnetic field lines may cross each other.

False. Magnetic field lines must never touch or cross each other. They must always go from north to south and never intersect.

How is a plotting compass used to map the magnetic field around a bar magnet?

A plotting compass is placed near the magnet. A dot is marked at each end of the compass needle in sequence. The compass is moved so the tail aligns with the new dot, and the process is repeated. The dots are then joined with a smooth curve to show the field line.

True or False? The force between a magnet and a magnetic material can be either attraction or repulsion.

False. The force between a magnet and a magnetic material is always attraction . Repulsion only occurs between two magnets with like poles facing each other.

Where is the magnetic field of a bar magnet strongest, and how is this shown on a field line diagram?

The magnetic field is strongest at the poles of the bar magnet. On a field line diagram, this is shown by the field lines being closest together at the poles.

Define earth's magnetic field .

The Earth's magnetic field is produced by movements of the liquid, iron-rich outer core of the Earth. It is similar in shape to the field of a bar magnet and its direction reverses periodically over geological time.

How does a magnetic compass work?

A magnetic compass contains a small bar magnet (the needle). The compass needle points in the direction of the Earth's magnetic field , so it always points roughly north in the absence of other magnets.

True or False? The geographic North Pole of the Earth acts as a magnetic north pole.

False. The geographic North Pole of the Earth actually acts as a magnetic south pole . This is why the north pole of a compass needle is attracted towards it.

The Earth's magnetic field is caused by movements in the .......... , .......... -rich outer core. These movements make the field .......... (changing over time).

The Earth's magnetic field is caused by movements in the liquid , iron -rich outer core. These movements make the field dynamic (changing over time).

Give two pieces of evidence that the Earth's magnetic field changes over time.

The positions of the magnetic north and south poles shift slowly over time. The direction of the field reverses periodically (the last reversal was about 800,000 years ago).

True or False? The Earth's magnetic field is generated by the solid inner core.

False. The Earth's magnetic field is generated by the liquid, iron-rich outer core . The inner core is solid and cannot generate the field.

Why does a compass needle move when placed near a magnet ?

A compass needle moves because it is itself a small permanent magnet . Magnetic forces act between it and the other magnet. Simply being made of metal is not sufficient — the material must be a magnet to respond.

A solenoid is a coil of wire that, when carrying a current, produces a magnetic field similar to that of a bar magnet . The field inside is strong and uniform, with one end acting as a north pole and the other as a south pole .

What is the shape of the magnetic field around a straight current-carrying wire?

The magnetic field around a straight current-carrying wire consists of concentric circles centred on the wire. The field is strongest closest to the wire and gets weaker with distance.

True or False? If the current through a wire is reversed, the direction of the magnetic field around it also reverses.

True. Reversing the direction of the current through the wire also reverses the direction of the magnetic field produced around it.

Define electromagnet .

An electromagnet is a solenoid with an iron core . Its magnetic field can be switched on and off with the current. The field strength can be increased by increasing the current, increasing the number of turns, or reducing the coil length.

The strength of the magnetic field around a solenoid can be increased by increasing the .......... , increasing the number of .......... , or inserting an .......... core.

The strength of the magnetic field around a solenoid can be increased by increasing the current , increasing the number of turns , or inserting an iron core.

What happens to the magnetic field around a current-carrying wire if there is no current flowing?

If there is no current flowing through the conductor, there will be no magnetic field produced around it.

True or False? The magnetic field pattern around a solenoid resembles that of a bar magnet.

True. The magnetic field around a solenoid is similar to that of a bar magnet : it has a north pole at one end and a south pole at the other, with the field strong and uniform inside.

Give two everyday uses of electromagnets.

Two everyday uses of electromagnets are: Scrapyard cranes (to pick up and release magnetic materials) Electric bells (where the electromagnet repeatedly attracts and releases an iron armature)

What is the motor effect ? (Higher Tier Only)

The motor effect occurs when a current-carrying conductor is placed in a magnetic field and experiences a force.

What three factors increase the size of the force on a current-carrying conductor in a magnetic field? (Higher Tier Only)

The force is increased by: Increasing the current Using a stronger magnet Increasing the length of conductor in the magnetic field

True or False? If a current-carrying wire is parallel to a magnetic field, the force on it is at its maximum. (Higher Tier Only)

False. If the wire and magnetic field are parallel , the force on the wire is zero . The force is maximum when the wire is perpendicular (at 90°) to the magnetic field.

The force on a conductor in a magnetic field is given by: F = .......... × .......... × .......... where F is in newtons. (Higher Tier Only)

The force on a conductor in a magnetic field is given by: F = B × I × L where F is in newtons. (B = magnetic flux density in tesla; I = current in amps; L = length in metres)

What is magnetic flux density ? (Higher Tier Only)

Magnetic flux density (symbol B, unit tesla , T) is a measure of the strength of a magnetic field.

True or False? The motor effect results from the interaction of two magnetic fields. (Higher Tier Only)

True. The motor effect results from the interaction of the magnetic field produced by the current in the wire and the external magnetic field (e.g. from a permanent magnet). This interaction produces a force on the wire.

What is Fleming's left-hand rule ? (Higher Tier Only)

Fleming's left-hand rule is used to find the direction of the force on a current-carrying conductor in a magnetic field. The First finger = field direction; se C ond finger = C urrent direction; TH umb = direction of TH rust (force).

In Fleming's left-hand rule, what does the thumb represent? (Higher Tier Only)

The thumb points in the direction of the force (or thrust) on the conductor — i.e. the direction in which the wire will move.

True or False? In Fleming's left-hand rule, the force, current, and magnetic field directions are all parallel to each other. (Higher Tier Only)

False. In Fleming's left-hand rule , the force, current, and magnetic field are all perpendicular (at right angles) to each other. This is why using the hand rule works — the three fingers point in mutually perpendicular directions.

In Fleming's left-hand rule, the .......... finger points in the direction of the magnetic field, the second finger points in the direction of the .......... , and the thumb points in the direction of the force . (Higher Tier Only)

In Fleming's left-hand rule, the first finger points in the direction of the magnetic field, the second finger points in the direction of the current , and the thumb points in the direction of the force .

The magnetic field points from left to right and the current flows upward . Using Fleming's left-hand rule, in which direction does the force act? (Higher Tier Only)

Using Fleming's left-hand rule with the field pointing right (first finger) and current upward (second finger), the thumb points out of the page — so the force acts towards the observer (out of the page).

True or False? Fleming's left-hand rule gives the direction of the magnetic field, not the force. (Higher Tier Only)

False. Fleming's left-hand rule gives the direction of the force (thrust) on the conductor — i.e. the direction in which the wire moves. The magnetic field direction is given by the first finger , not the rule's output.

What is a split-ring commutator ? (Higher Tier Only)

The split-ring commutator (or split ring) in a d.c. electric motor reverses the direction of the current through the coil every half turn . This ensures the coil continues to rotate in the same direction .

Why does a current-carrying coil rotate in a d.c. electric motor? (Higher Tier Only)

Forces act in opposite directions on each side of the coil (from the motor effect). These opposing forces create a turning effect , causing the coil to rotate .

True or False? In a d.c. motor, the coil continues to spin even when the split ring is not in contact with the carbon brushes. (Higher Tier Only)

False. When the split ring is not in contact with the carbon brushes (when the coil is vertical), no current flows and no force acts. The coil continues due to its momentum — not because of the motor effect .

How can the speed of a d.c. motor be increased? (Higher Tier Only)

The speed of a d.c. motor can be increased by: Increasing the current Using a stronger magnet

In a d.c. electric motor, the coil is connected to the circuit via a .......... and conducting .......... brushes. (Higher Tier Only)

In a d.c. electric motor, the coil is connected to the circuit via a split ring and conducting carbon brushes.

How can the direction of rotation of a d.c. motor be reversed? (Higher Tier Only)

The direction of rotation can be reversed by: Reversing the direction of the current supply Reversing the direction of the magnetic field (swapping the poles of the magnet)

True or False? Adding more turns to the coil of a d.c. motor increases the force it supplies. (Higher Tier Only)

True. Adding more turns to the coil increases the total force supplied by the motor, as more conductor length interacts with the magnetic field.

GCSEScienceAQACombined Science: SynergyPhysical SciencesFlashcardsInteractions Over Small & Large DistancesMagnetism & Electromagnetism

Magnetism & Electromagnetism (AQA GCSE Combined Science: Synergy: Physical Sciences): Flashcards

Exam code: 8465

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Define Law of Magnetism.

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Cards in this collection (51)

Define Law of Magnetism.
The Law of Magnetism states that two like poles repel each other and two unlike poles attract each other. The attraction and repulsion between magnetic poles are examples of non-contact forces.
True or False?
All metals are magnetic materials.
False.
Only a few metals are magnetic materials: iron, cobalt, nickel, and steel (an alloy containing iron). Metals such as copper, gold, and aluminium are not magnetic.
Define induced magnet.
An induced magnet is a magnetic material that temporarily becomes a magnet when placed in a magnetic field. It loses most or all of its magnetism quickly when removed from the field.
How can you test whether a material is a magnet or just a magnetic material?
Bring the material close to a known magnet. If it can be repelled, it is itself a magnet. If it can only be attracted and never repelled, it is a magnetic material (not a magnet).
A permanent magnet is made from a material such as .......... and produces its own .......... field without losing its magnetism.
A permanent magnet is made from a material such as steel and produces its own magnetic field without losing its magnetism.
When a magnetic material is brought close to a permanent magnet, which pole does the near end of the material develop?
The end of the magnetic material closest to the magnet develops the opposite pole to the magnet's nearest pole. This is why magnetic materials are always attracted to magnets.
True or False?
The poles of a magnet are called positive and negative.
False.
The poles of a magnet are called North and South — not positive and negative (those terms apply to electrical charge, not magnetism).
List the four magnetic materials.
The four magnetic materials are:
1. Iron
2. Cobalt
3. Nickel
4. Steel (an alloy of iron)
Define magnetic field.
A magnetic field is the region around a magnet where a force acts on another magnet or on a magnetic material (iron, steel, cobalt, and nickel). The field is strongest at the poles of the magnet.
In what direction do magnetic field lines always point around a bar magnet?
Magnetic field lines always point from the north pole to the south pole of a magnet. This direction is shown by an arrow midway along each line.
The strength of a magnetic field is shown by the .......... of the field lines: field lines .......... together indicate a stronger field.
The strength of a magnetic field is shown by the spacing of the field lines: field lines closer together indicate a stronger field.
Define uniform magnetic field.
A uniform magnetic field has the same strength and direction at all points. It is represented by parallel, equally spaced field lines with arrows all pointing in the same direction. It is produced between opposite poles held close together.
True or False?
Magnetic field lines may cross each other.
False.
Magnetic field lines must never touch or cross each other. They must always go from north to south and never intersect.
How is a plotting compass used to map the magnetic field around a bar magnet?
A plotting compass is placed near the magnet. A dot is marked at each end of the compass needle in sequence. The compass is moved so the tail aligns with the new dot, and the process is repeated. The dots are then joined with a smooth curve to show the field line.
True or False?
The force between a magnet and a magnetic material can be either attraction or repulsion.
False.
The force between a magnet and a magnetic material is always attraction. Repulsion only occurs between two magnets with like poles facing each other.
Where is the magnetic field of a bar magnet strongest, and how is this shown on a field line diagram?
The magnetic field is strongest at the poles of the bar magnet. On a field line diagram, this is shown by the field lines being closest together at the poles.
Define earth's magnetic field.
The Earth's magnetic field is produced by movements of the liquid, iron-rich outer core of the Earth. It is similar in shape to the field of a bar magnet and its direction reverses periodically over geological time.
How does a magnetic compass work?
A magnetic compass contains a small bar magnet (the needle). The compass needle points in the direction of the Earth's magnetic field, so it always points roughly north in the absence of other magnets.
True or False?
The geographic North Pole of the Earth acts as a magnetic north pole.
False.
The geographic North Pole of the Earth actually acts as a magnetic south pole. This is why the north pole of a compass needle is attracted towards it.
The Earth's magnetic field is caused by movements in the .........., .......... -rich outer core. These movements make the field .......... (changing over time).
The Earth's magnetic field is caused by movements in the liquid, iron-rich outer core. These movements make the field dynamic (changing over time).
Give two pieces of evidence that the Earth's magnetic field changes over time.
1. The positions of the magnetic north and south poles shift slowly over time.
2. The direction of the field reverses periodically (the last reversal was about 800,000 years ago).
True or False?
The Earth's magnetic field is generated by the solid inner core.
False.
The Earth's magnetic field is generated by the liquid, iron-rich outer core. The inner core is solid and cannot generate the field.
Why does a compass needle move when placed near a magnet?
A compass needle moves because it is itself a small permanent magnet. Magnetic forces act between it and the other magnet. Simply being made of metal is not sufficient — the material must be a magnet to respond.
Define solenoid.
A solenoid is a coil of wire that, when carrying a current, produces a magnetic field similar to that of a bar magnet. The field inside is strong and uniform, with one end acting as a north pole and the other as a south pole.
What is the shape of the magnetic field around a straight current-carrying wire?
The magnetic field around a straight current-carrying wire consists of concentric circles centred on the wire. The field is strongest closest to the wire and gets weaker with distance.
True or False?
If the current through a wire is reversed, the direction of the magnetic field around it also reverses.
True.
Reversing the direction of the current through the wire also reverses the direction of the magnetic field produced around it.
Define electromagnet.
An electromagnet is a solenoid with an iron core. Its magnetic field can be switched on and off with the current. The field strength can be increased by increasing the current, increasing the number of turns, or reducing the coil length.
The strength of the magnetic field around a solenoid can be increased by increasing the .........., increasing the number of .........., or inserting an .......... core.
The strength of the magnetic field around a solenoid can be increased by increasing the current, increasing the number of turns, or inserting an iron core.
What happens to the magnetic field around a current-carrying wire if there is no current flowing?
If there is no current flowing through the conductor, there will be no magnetic field produced around it.
True or False?
The magnetic field pattern around a solenoid resembles that of a bar magnet.
True.
The magnetic field around a solenoid is similar to that of a bar magnet: it has a north pole at one end and a south pole at the other, with the field strong and uniform inside.
Give two everyday uses of electromagnets.
Two everyday uses of electromagnets are:
1. Scrapyard cranes (to pick up and release magnetic materials)
2. Electric bells (where the electromagnet repeatedly attracts and releases an iron armature)
What is the motor effect?
(Higher Tier Only)
The motor effect occurs when a current-carrying conductor is placed in a magnetic field and experiences a force.
What three factors increase the size of the force on a current-carrying conductor in a magnetic field?
(Higher Tier Only)
The force is increased by:
1. Increasing the current
2. Using a stronger magnet
3. Increasing the length of conductor in the magnetic field
True or False?
If a current-carrying wire is parallel to a magnetic field, the force on it is at its maximum.
(Higher Tier Only)
False.
If the wire and magnetic field are parallel, the force on the wire is zero. The force is maximum when the wire is perpendicular (at 90°) to the magnetic field.
The force on a conductor in a magnetic field is given by: F = .......... × .......... × .......... where F is in newtons.
(Higher Tier Only)
The force on a conductor in a magnetic field is given by: F = B × I × L where F is in newtons.
(B = magnetic flux density in tesla; I = current in amps; L = length in metres)
What is magnetic flux density?
(Higher Tier Only)
Magnetic flux density (symbol B, unit tesla, T) is a measure of the strength of a magnetic field.
A wire of length 0.1 m carries a current of 2 A in a magnetic field of flux density 0.5 T. Calculate the force on the wire.
(Higher Tier Only)
$F = B I L$
F = 0.5 × 2 × 0.1
F = 0.1 N
True or False?
The motor effect results from the interaction of two magnetic fields.
(Higher Tier Only)
True.
The motor effect results from the interaction of the magnetic field produced by the current in the wire and the external magnetic field (e.g. from a permanent magnet). This interaction produces a force on the wire.
What is Fleming's left-hand rule?
(Higher Tier Only)
Fleming's left-hand rule is used to find the direction of the force on a current-carrying conductor in a magnetic field. The First finger = field direction; seCond finger = Current direction; THumb = direction of THrust (force).
In Fleming's left-hand rule, what does the thumb represent?
(Higher Tier Only)
The thumb points in the direction of the force (or thrust) on the conductor — i.e. the direction in which the wire will move.
True or False?
In Fleming's left-hand rule, the force, current, and magnetic field directions are all parallel to each other.
(Higher Tier Only)
False.
In Fleming's left-hand rule, the force, current, and magnetic field are all perpendicular (at right angles) to each other. This is why using the hand rule works — the three fingers point in mutually perpendicular directions.
In Fleming's left-hand rule, the .......... finger points in the direction of the magnetic field, the second finger points in the direction of the .........., and the thumb points in the direction of the force.
(Higher Tier Only)
In Fleming's left-hand rule, the first finger points in the direction of the magnetic field, the second finger points in the direction of the current, and the thumb points in the direction of the force.
The magnetic field points from left to right and the current flows upward. Using Fleming's left-hand rule, in which direction does the force act?
(Higher Tier Only)
Using Fleming's left-hand rule with the field pointing right (first finger) and current upward (second finger), the thumb points out of the page — so the force acts towards the observer (out of the page).
True or False?
Fleming's left-hand rule gives the direction of the magnetic field, not the force.
(Higher Tier Only)
False.
Fleming's left-hand rule gives the direction of the force (thrust) on the conductor — i.e. the direction in which the wire moves. The magnetic field direction is given by the first finger, not the rule's output.
What is a split-ring commutator?
(Higher Tier Only)
The split-ring commutator (or split ring) in a d.c. electric motor reverses the direction of the current through the coil every half turn. This ensures the coil continues to rotate in the same direction.
Why does a current-carrying coil rotate in a d.c. electric motor?
(Higher Tier Only)
Forces act in opposite directions on each side of the coil (from the motor effect). These opposing forces create a turning effect, causing the coil to rotate.
True or False?
In a d.c. motor, the coil continues to spin even when the split ring is not in contact with the carbon brushes.
(Higher Tier Only)
False.
When the split ring is not in contact with the carbon brushes (when the coil is vertical), no current flows and no force acts. The coil continues due to its momentum — not because of the motor effect.
How can the speed of a d.c. motor be increased?
(Higher Tier Only)
The speed of a d.c. motor can be increased by:
1. Increasing the current
2. Using a stronger magnet
In a d.c. electric motor, the coil is connected to the circuit via a .......... and conducting .......... brushes.
(Higher Tier Only)
In a d.c. electric motor, the coil is connected to the circuit via a split ring and conducting carbon brushes.
How can the direction of rotation of a d.c. motor be reversed?
(Higher Tier Only)
The direction of rotation can be reversed by:
1. Reversing the direction of the current supply
2. Reversing the direction of the magnetic field (swapping the poles of the magnet)
True or False?
Adding more turns to the coil of a d.c. motor increases the force it supplies.
(Higher Tier Only)
True.
Adding more turns to the coil increases the total force supplied by the motor, as more conductor length interacts with the magnetic field.

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