Define the term magnet.
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Define the term magnet.
Magnets are objects with north and south poles. They attract magnetic materials and can attract or repel other magnets.
Name the two poles of a magnet.
The two poles of a magnet are the north and south poles.
True or False?
Opposite poles attract.
True.
Opposite poles attract.
Define the meaning of the phrase like poles.
Like poles have the same polarity (e.g. north and north) and they repel each other.
Define the meaning of the phrase unlike poles.
Unlike poles have opposite polarities (e.g. north and south) and attract each other.
What does it mean for a material to be magnetic?
A magnetic material experiences an attractive force when placed in a magnetic field and can be magnetised to form a magnet.
State the meaning of the term non-magnetic material.
Non-magnetic materials do not experience a force when placed in a magnetic field.
True or False?
Only a magnet can repel another magnet.
True.
Only a magnet can repel another magnet.
What is the test for a magnet?
To test whether a material is a magnet, it should be brought close to a known magnet. If it can be repelled by the known magnet, then the material itself is a magnet.
True or False?
The south pole of one magnet repels the north pole of another magnet.
False.
Opposite poles attract.
Define the term magnetic field.
A magnetic field is the region around a magnet where a force acts on another magnet or on a magnetic material.
Define the term uniform magnetic field.
A uniform magnetic field is a magnetic field that has the same strength and direction at all points.
How is a uniform magnetic field represented in diagrams?
In a uniform magnetic field, the magnetic field lines are equally spaced, and all arrows point in the same direction.
What are magnetic field lines?
Magnetic field lines are lines drawn to represent the strength and direction of a magnetic field.
What are the two rules for drawing magnetic field lines?
Two rules for drawing magnetic field lines are:
Magnetic field lines must always go from north to south (indicated by an arrow midway along the line)
Field lines must never touch or cross other field lines
True or False?
The magnetic field is strongest at the poles of a bar magnet.
True.
The magnetic field is strongest at the poles of a bar magnet, where the magnetic field lines are closest together.
What do closely spaced magnetic field lines indicate?
Closely spaced magnetic field lines indicate a strong magnetic field.
What do widely spaced magnetic field lines indicate?
Widely spaced magnetic field lines indicate a weak magnetic field.
The magnetic field of a bar magnet gets weaker further from the magnet. How is this represented in a diagram?
To represent the fact that a bar magnet's field weakens with distance from the magnet, the field lines get further apart further from the bar magnet.
Define the term permanent magnet.
Permanent magnets produce their own magnetic field and do not lose their magnetism.
What is induced magnetism?
Induced magnetism is when a magnetic material is placed in a magnetic field and the material can temporarily be turned into a magnet.
Define the term magnetic material.
Magnetic materials are materials that are attracted to a magnet.
True or False?
Induced magnets retain their magnetism after being removed from the magnetic field.
False.
Induced magnets lose most/all of their magnetism quickly after being removed from the magnetic field.
What happens to the ends of a magnetic material when it becomes an induced magnet?
When magnetism is induced in a material, one end of the material will become a north pole, and the other end will become a south pole.
True or False?
Aluminium is a magnetic material.
False.
Aluminium is not a magnetic material.
What is an example of a magnetic material?
Iron, cobalt, nickel, and steel (an alloy containing iron) are examples of magnetic materials.
How can you determine which pole is induced at a particular end of a magnetic material?
To determine which pole is induced at one end of a magnetic material, hold a south pole near that end. If the end is repelled, it is a south pole. If it attracts, it is a north pole.
What is an example of a non-magnetic material?
Any material other than iron, cobalt, nickel, and steel (or alloys containing these metals) is a non-magnetic material. For example, aluminum, copper, wood, plastic, etc.
True or False?
The south pole of an induced magnet will repel an iron paperclip.
False.
The iron paperclip, a magnetic material, can only be attracted by a magnet, not repelled.
What are the two principal ways of plotting the magnetic field around a bar magnet?
The two principal ways of plotting the magnetic field around a bar magnet are using iron filings and using plotting compasses.
What is the method for plotting magnetic field lines using iron filings?
To plot magnetic field lines using iron filings:
Place a piece of paper on top of the magnet
Gently sprinkle iron filings on top of the paper
Carefully tap the paper to allow the iron filings to settle on the field lines
What is the method for plotting magnetic field lines using a plotting compass?
To plot magnetic field lines using a plotting compass:
Place the magnet on top of a piece of paper and draw a dot at one end
Place a plotting compass next to the dot so that one end of the needle points towards the dot
Draw a new dot at the other side of the compass needle
Move the compass to point towards the new dot
Repeat the process to create a chain of dots representing the magnetic field line
True or False?
The direction of the magnetic field line plotted using a compass is the same as the direction of the plotting compass.
True.
The direction of the magnetic field line plotted using a compass is the same as the direction of the plotting compass.
What do you need to do after creating a chain of dots using a plotting compass?
After creating a chain of dots using a plotting compass, you need to remove the compass and link the dots using a smooth curve to represent the magnetic field line.
How can you plot multiple magnetic field lines around a bar magnet?
To plot multiple magnetic field lines around a bar magnet, you need to repeat the process of using the plotting compass several times, starting from different points on the magnet.
True or False?
The compass needle points in the opposite direction to the arrows on the field lines.
False.
The needle points in the same direction as the arrows on the field lines.
True or False?
In the iron filing experiment, more filings will gather near the magnet's poles than at the edge of the paper.
True.
The magnetic field is stronger at the magnet's poles, so more iron filings will gather here.
What two factors that affect the strength of the magnetic field produced by a current in a wire?
Two factors affecting magnetic field strength are:
the size of the current
the distance from the wire
True or False?
A current-carrying wire produces a uniform magnetic field.
False.
A current-carrying wire produces a non-uniform, circular magnetic field.
True or False?
The right hand rule shows the direction of current in a wire when the direction of the field lines is known.
True.
In the right hand rule, the fingers show the direction of the magnetic field and the thumb points in the direction of the current.
Is a magnetic field produced by a wire when the current is 0 A?
No, a magnetic field is not produced by a wire when there is no current.
True or False?
When the current is greater, the magnetic field lines are further apart from each other.
False.
When the current is greater, the magnetic field lines are closer together because the field is stronger.
What happens to a current-carrying conductor in a magnetic field?
A current-carrying conductor in the presence of a magnetic field experiences a force, resulting in its movement or deflection.
True or False?
A current-carrying conductor will only experience a force if the current is parallel to the magnetic field lines.
False.
A current-carrying conductor will only experience a force if the current through it is perpendicular to the direction of the magnetic field lines.
What type of motor can the motor effect be used to create?
The motor effect can be used to create a simple d.c. electric motor.
Describe a simple d.c. electric motor.
A simple d.c. electric motor consists of a coil of wire (which is free to rotate) which is carrying current and is positioned in a uniform magnetic field.
What causes the coil in a d.c. motor to rotate?
The coil in a d.c. motor rotates due to experiencing a force (and therefore a turning effect) when an electric current flows through it in a magnetic field.
What factors increase the speed of rotation of a d.c. motor?
The factors that increase the speed of rotation of a d.c. motor are:
increasing the current through the rotating coil
using a stronger magnet on either side of the rotating coil
What changes the direction of rotation of the coil in a d.c. motor?
The direction of rotation of the coil in a d.c. motor can be changed by:
reversing the direction of the current
reversing the poles of the magnet
What increases the force supplied by a d.c. motor?
The force supplied by a d.c. motor is increased by:
increasing the current in the coil
increasing the strength of the magnetic field
adding more turns to the coil
How can you determine the direction of rotation of the coil in a d.c. motor?
You determine the direction of rotation of the coil in a d.c. motor by:
using Fleming's left-hand rule to find the force direction
determining the direction of rotation of the coil based on the forces
What is Fleming's left-hand rule used for?
Fleming's left-hand rule is used to determine the direction of the force acting on a current-carrying conductor in a magnetic field, as well as the direction of the current and magnetic field.
State the quantity represented by each finger in Fleming's left-hand rule.
The quantity represented by each finger in Fleming's left-hand rule is:
First finger is the direction of the magnetic field
Second finger is the direction of the current in the wire
Thumb is the direction of the force which shows the direction of the movement of the wire
True or False?
The direction of the force on a current-carrying wire depends on the direction of the current and the magnetic field.
True.
The direction of the force on a current-carrying wire depends on the direction of the current and the direction of the magnetic field, both of which should be perpendicular to each other.
True or False?
The direction of the force on a current-carrying wire depends on the direction of the current and the magnetic field.
True.
The direction of the force on a current-carrying wire depends on the direction of the current and the direction of the magnetic field, both of which should be perpendicular to each other.
How is an electromagnet made?
A coil of current-carrying wire is wrapped around an iron core.
What is the difference between a solenoid and an electromagnet?
A solenoid is a coil of wire carrying current, while an electromagnet is a coil of wire carrying current that is wrapped around an iron core.
True or False?
Adding more turns to the coil increases the strength of the electromagnet.
True.
Adding more turns to the coil does increase the strength of the electromagnet.
How is the direction of an electromagnet's field reversed?
Reversing the direction of the current reverses the direction of the magnetic field.
What is the pattern of the magnetic field due to the current in a straight wire?
The magnetic field due to a current in a straight wire forms concentric circles that get further apart with increasing distance from the wire.
What rule is used to determine the direction of the magnetic field around a current carrying wire?
The right-hand thumb rule can be used to determine the direction of the magnetic field around a current-carrying wire.
What pattern is formed by the magnetic field inside a current-carrying solenoid?
Inside a solenoid, the magnetic field is uniform, so the field lines are equally spaced straight lines pointing in the same direction.
True or False?
When viewed from the end of a solenoid, the pole is a north pole if the current travels clockwise around the coil.
False.
When viewed from the end of a solenoid, the pole is a south pole if the current travels clockwise around the coil.
How can the strength of the magnetic field around a solenoid be increased?
The strength of the magnetic field around a solenoid can be increased by:
increasing the current
increasing the number of turns on the coil
adding a soft iron core to the centre of the coil
Changing the direction of the current through a solenoid would have what effect on the magnetic field around it?
Changing the direction of the current through a solenoid would change the direction of the magnetic field around it.
What is the magnetic field pattern around a flat circular coil?
When a wire is looped into a coil, the magnetic field lines circle around each part of the coil, passing through the centre of it.
When does the maximum force experienced by a charged particle entering a magnetic field occur?
The maximum force experienced by a charged particle entering a magnetic field occurs when the particle is traveling perpendicular to the field lines.
Describe the behaviour of moving charged particles in a magnetic field.
Charged particles in a magnetic field experience a force which causes them to deflect.
What can be used to determine the direction of the force experienced by an electron in a magnetic field?
The direction of the force experienced by an electron in a magnetic field can be determined using Fleming's left-hand rule, where the second finger (representing current) points opposite to the direction of electron flow.
True or False?
In a uniform field, an electron experiences a force perpendicular to the direction of the magnetic field.
True.
The force experienced by a moving charge is always perpendicular to the magnetic field.
True or False?
In a uniform magnetic field from left to right, a stationary proton experiences a downward force.
False.
If the charge is stationary, it does not experience a force in a magnetic field.