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Draw a diagram of a bar magnet with magnetic field lines.
Lines flow north to south
A DC generator has half contact brushes instead of full. TRUE or FALSE
FALSE (it has half RINGS)
Define AC
Alternating current - current is constantly changing direction
Iron core
What do we call loops of wire around an iron core?
Solenoid
What happens when you change the direction of current in an electromagnet
Poles switch/magnetic field changes direction
What is used to increase the voltage of AC current
Step up transformer
How can you change the direction of the magnetic field in an electromagnet
Change the direction of current
What is the working principle of an electric generator?
Electromagnetic induction - rotating coil in magnetic field produced current
When a wire carrying current is placed in a magnetic field, what happens?
A force acts on the wire
Name three ways to increase the strength of an electric generator
More loops in coil
Stronger magnet
Increase speed of rotation
What does fleming's left hand rule help us to determine?
Direction of force on wire carrying current
What does Fleming's right hand rule help us to determine?
Direction of current in electric generator
Define electromagnetic induction
Change/movement of magnetic field produces current
Why does current change direction in an AC generator?
Give three advantages of AC over DC current
Voltage can be regulated
Stronger
Safer
Why does a compass have a magnetic needle in it?
Why is DC more dangerous?
Force does not change and will keep you stuck to the wire
What is the opposite of electromagnetic induction?
Current produces magnetic field around wire
Name two ways to turn an ordinary iron nail into a magnet
Touch a strong magnet
Attach to a solenoid and a battery to make an electromagnet
Draw and label an AC generator
Draw and label a diagram of an electric bell
Bell, hammer, contact point, solenoid, cell, switch
State 5 properties of magnets
Attract iron, align north/south, like poles repel & unlike poles attract, poles cannot be separated, iron can be magnetized by touching strong magnet
Why is an AC generator stronger than a DC generator?
Current in both directions is captured due to full rings.
Describe the working of an electric bell
When the contact point is touching, current is flowing, the electromagnet is on, it attracts the hammer
Now the contact point is not touching, current is not flowing, the electromagnet is off, releases the hammer
REPEAT