Physics IGCSE

Question 1

Why will E.M.F induce?

Answer 1

If there is movement between conductor and MF

Also if conductor is stationary in changing MF

conductor cuts through wire if perpendicular.

Question 2

What is Lenz’s Law

Answer 2

Direction of induced potential difference always opposes change that produces it

Tries to stop wire or magnet from moving

Question 3

Factors affecting EM imduction size

Answer 3

• speed in which wire is moved
• size of coil
• strength of magnetic field

Question 4

What is an AC generator

Answer 4

Type of generator that converts mechanical energy into electrical energy in form of alternating current

Question 5

Slip Rings

Answer 5

Transmits electrical power into coil which is at rest to make it move, E.M.F alternates

Question 6

Carbon Brushes

Answer 6

Makes constant contact between coil and circuit to avoid wires becoming twisted.

Question 7

What is alternating current

Answer 7

Current flow created by electrons continuously changing directions.

Question 8

(A.C) What happens when coil turns in one direction

Answer 8

Pointer deflected one way, then, the other one.
Because coil cuts through MF lines and a E.M.F is induced in coil

Question 9

What happens when current flows through a wire

Answer 9

A MF is produced around the wire
Produces lines that are circular around it
As distances increases circules get further apart

Question 10

MF around solenoid

Answer 10

Similiar to bar magnet, strong and uniform
Clockwise - south

Question 10

What is a electromagnet?

Answer 10

Soft iron + coil

Question 11

When is there magnetic field in electromagnets

Answer 11

Current flowing there will be MF
no current flowing, no MF

Question 12

Factors affecting MF strength around a solenoid

Answer 12

• increasing size of current
• ## increase number of coils

Question 13

Factors affecting electromagnet

Answer 13

• increase current

Question 14

Relay

Answer 14

Electromagnets are used in relay circuits
Loudspeakers use oscillation to generate vibrations for sound

Question 15

Faradays Law

Answer 15

Wire close to changing MF will experience a induced EMF

Question 16

Experiment for electromagnetic induction

Answer 16

Move bar through a wire coil, see oscillations in galvanometer, see current

Question 17

Factors affecting force increase

Answer 17

• increase MF
• increase current
• increase wires
• increase turns
• increase length

Question 18

Factors affecting turning force of a motor

Answer 18

• increase current
• increase number of turns

Question 19

Split Rings

Answer 19

Once coil has rotated 180, current continues to flow in clockwise. Split ring makes sure direction of current stays the same só force also

Question 20

What is magnetic effect of a current

Answer 20

• created when current flows through a wire
• needle of compass points in direction of MF

Question 21

What will happen once a current carrying conductor is places in a MF

Answer 21

Will experience a force if wire is perpendicular because MF exerts a force on each individual elecrrom

Question 22

Deflect

Answer 22

When a charged particle passes through MF, field exerts force on particle, deflects.
Force is always at 90
Use left hand rule.

Question 23

Operation of D.C motor

Answer 23

When current is flowing at 90.
Current creates a MF around coil
Force exerted into coil
Current will flow into opposite direction on each side of coil
Force produced from MF will push one side of coil up and other side down
Cause coil to rotate
Vertical position

Question 24

Factors affecting D.C motor

Answer 24

• speed at which coil rotates
• direction of rotation