Extra Related Information

Question 1

Electromagnetism

1) When a current flows through a wire, a _______ ____ is created _____ the wire
2) The field is made up of ________ circles that are ________ to the wire, with the wire in the _______.
3) You can see this by placing a ______ near a wire that is carrying ______. As you move the compass, the ______ will _____ the _______ of the magnetic field.

Answer 1

Current through wire - Magnetic field created around it

Field - concentric circles perpendicular to wire - wire in the centre

Compass near wire carrying current. Move compass, needle traces direction of magnetic field

Question 2

Electromagnetism

4) Changing the direction of the current changes the _______ of the ________ field - use the _____ ____ thumb rule to work out which way it goes.

Answer 2

Current direction changes - Magnetic field direction changes as well - use right hand thumb rule to find out which way it goes

Question 3

Right hand thumb rule

Thumb points along the direction of the _______

Current carrying wire goes through the ______ of the hand.

All other fingers give the _______ of the _______.
Check CGP

Answer 3

Thumb points to direction of current

Current carrying wire goes through centre of hand

Other fingers point to direction of field - usually wrapped around the current carrying wire - perpendicular to direction of current

Question 4

Electromagnetism

5) Strength of the magnetic field is affected by changes in ________ and the ________ from the wire.

The _____ the current through the wire, or the ______ to the wire you are, the stronger the field is.

Answer 4

Strength of field - affected by changes in current and distance from the wire

More current or closer to the wire - stronger the magnetic field

Question 5

Solenoids

A solenoid is a ___ of ____.

1) You can increase the ______ of the magnetic field that a _____-carrying wire produces by _____ the wire into a ____ called a _______.
2) The magnetic field strength _______ because the fields around each ____ (or loop) of wire ____ up with each other - and so ____ together

Answer 5

Increase strength of magnetic field from current-carrying wire - wrap the wire into a coil (aka a solenoid)

Magnetic field strength increases, fields around each turn/loop line up with each other - so they add together

Question 6

Solenoids

3) The magnetic field _____ a solenoid is strong and _______ (it has the same ______ and _______ at every point in the region).
4) _______ the coil, the magnetic field is just like the one round a ___ magnet.

Answer 6

Inside coil - magnetic field strong and uniform (same strength and direction at every point in the region).

Outside coil - magnetic field is just like round a bar magnet

Question 7

Solenoids
5) The field strength of the solenoid can be increased by

• Increasing the _______ through the coil
• Increasing the number of ____ but keeping the _____ the same
• Decreasing the ______ whilst keeping the number of ____ the same.

Answer 7

Increase current through coil
Increase number of turns whilst keeping length the same

Decrease length whilst keeping number of turns the same

Question 8

Solenoids

6) Also, you can add an ____ core in the ______ of the coil. The ____ core becomes an ______ magnet whenever _______ is flowing, so the field ______ of the solenoid is ________.
7) A ______-carrying solenoid with an _____ core is an _________ - a magnet with a magnetic field that can be turned __ and ___ by turning the _______ on and off.

Answer 8

Add iron core in the centre of solenoid - iron core becomes an induced magnet when a current is flowing - so magnetic field strength of solenoid increases

Current-carrying solenoid with iron core - An Electromagnet

Electromagnet - magnet with a magnetic field that can be turned on and off by turning the current on and off