Physics || Transformers P12+P13

Question 1

Magnetic Field Shape?

Answer 1

Circular

North and South poles are strongest parts of the magnets.

Goes around the magnet.

Question 2

Force Formula?

Answer 2

Force =

Magnetic Field Density (Flux) 
x 
Current (Amps)
x
Length of Wire (Metres)

Question 3

Direct Current?

Answer 3

Current is continuous and does not change,

Use this in battery’s,

Used for creating permanent magnets.

Question 4

Alternating Current?

Answer 4

Used for making magnets that are induced (can change),

Can change voltage.

Question 5

Flaming’s Left Hand Rule?

Answer 5

Index - Direction of magnetic field,

Middle - Direction of current,

Thumb - Is the direction of the motion the wire will move in.

Question 6

Right Hand Rule?

Answer 6

Thumb points in direction of current,

The way your fingers wrap around is the way the magnetic field is spinning.

Question 7

Power Formula?

Answer 7

Energy Transferred / Time Taken (In Other Cases).

Question 8

Formula for Transformers?

Answer 8

Vp x Ip = Vs x Is,

(Primary Voltage x Primary Current = Secondary Voltage x Secondary Current),

Both sides should be equal.

Question 9

Producing A Current By Changing The Magnetic Field?

Answer 9

Moving/Rotating the magnet inside of the solenoid,

Moving/Rotating a conductor in a magnetic field.

Turning the magnet (or conductor) the opposite way to the magnetic field, the potential difference/current will change direction with it,

This creates an alternating current.

Question 10

Solenoid?

Answer 10

Coil of wire.

Question 11

Electromagnet?

Answer 11

Solenoid with an electric current running through it,

Can be turned on and off using an electric current switch.

Question 12

Direct Current on Amplifier?

Answer 12

Positive, Straight Line.

Question 13

Alternating Current On Amplifier?

Answer 13

Positive and Negative Waves.

Question 14

Current Is Created Inside Wire Without Electricity By?

Answer 14

Moving electrons,

We do this by using a magnet.

Question 15

Frequency of Generator?

Answer 15

Speed of the magnet spinning in the generator.

Question 16

How Do We Make Generators Stronger?

Answer 16

More coils,
Spin magnet faster,
Introduce an iron core.

Question 17

Make An Electromagnet Stronger?

Answer 17

Add a higher current,
Introduce an iron core,
Add more coils.

Question 18

Why Do We Send High Voltage Around National Grid?

Answer 18

So we don’t waste energy through heat in the wires,

High Voltage = Low Current,

Low Voltage = High Current,

Low current means that less electrons hit off each other, resulting in less friction, resulting in less heat energy been given off through the wires. Less energy is wasted with high voltage. This high voltage is Steped Down using a transformer.

Question 19

Transformer Types?

Answer 19

Step Down,
Step Up.

Transformers use a larger amount of coils at the end of the magnet if they are “stepping up” the voltage.

This is the same for “stepping down” the voltage but the amount of coils is less on the secondary side of the magnet than the primary side.

Question 20

Magnetic Filed Lines Direction?

Answer 20

The magnetic field always travels North to South.

Question 21

We Can Tell A Magnetic Field Diagram Is Strong Because?

Answer 21

The lines of the magnetic field are closer together.

Question 22

Plotting Compasses Show?

Answer 22

The direction of the magnetic field,

This happens because the needle inside the compass is a tiny bar magnet,

When they are not near a magnet, the plotting compasses always point towards the Earths North Pole. This happens because the Earth generates its own magnetic field. The core of the Earth is magnetic.

Question 23

Induced Magnet?

Answer 23

A temporary magnetic field is made when they are placed inside another magnetic field,

Placing any magnetic material (Main ones are iron, nickel and cobalt) inside of a magnetic field creates an induced magnet,

When this magnetic material is taken away from the magnetic field, the material stops producing a magnetic field.

Question 24

Permanent Magnet?

Answer 24

Produces a magnetic field all of the time:

Question 25

Hard Materials?

Answer 25

E.g. Steel (magnetic because it contains iron) looses magnetism more slowly.

Question 26

Soft Materials?

Answer 26

Pure iron and pure nickel-iron loose their magnetism more quickly.

Question 27

Uses For Induced Magnets?

Answer 27

Fridge Doors, Doorbells, Cranes, Speakers, MRI Machines.

Question 28

Magnetic Field Is Made Of?

Answer 28

Concentric circles perpendicular to the wire.

Question 29

The Motor Effect?

Answer 29

A wire had to be 90 degrees to the magnetic field,

A wire won’t experience any for at all if not at an angle,

Force always acts the same direction to the magnetic field and current. So changing the current or magnetic field direction will change the direction of the movement.

Question 30

Electrical Power Formula?

Answer 30

Voltage x Current,

Primary Power can be found by: Primary Voltage x Primary Current,

Secondary Power can be found by:
Secondary Voltage x Secondary Current.