Motor Effect

Question 1

when a current flows through a wire a what is produced around the wire

Answer 1

magnetic field

Question 2

what is an electromagnet

Answer 2

a magnet that can be turned off and on (magnetically soft)

Question 3

what is the electromagnet in a circuit

Answer 3

a solenoid with a soft iron core

Question 4

what is a soft magnet

Answer 4

can be magnetised and demagnetised easily

Question 5

what is a hard magnet

Answer 5

hard to magnetise but once done it stays magnetised

Question 6

where is a magnetic field produced on a wire

Answer 6

around a current carrying conductor

Question 7

how can you make the magnetic field in a circuit stronger

Answer 7

add more loops to the coil of the solenoid or increase the current by adding more voltage

Question 8

what is the motor effect

Answer 8

converting electrical energy into kinetic energy

Question 9

8 steps for how motor effect is used in a bell (picture found in folder)

Answer 9

1) switch closed –> circuit complete
2) magnet is magnetised by the electrical flow
3) armature is attracted towards the magnet enough for the hammer to hit the bell
4) the springy bit of metal is brought with it to the magnet
5) when springy strip of metal moves away from the contact point, circuit is broken
6) the electromagnet then becomes de-magnetised
7) attraction of armature stops and springs back to contact screw
8) this closes the circuit again, magnetising the magnet and repeating the process, the bell rings again quickly

Question 10

8 steps for how a battery works in a car

Answer 10

1) switch closed –> circuit complete and current flowing
2) magnet magnetised by electrical flow
3) iron rockers are attracted to north pole of the magnet
4) pivot makes other wend of the arm create contact with the second circuit (2 circuits for safety)
5) circuit complete –> current flows
6) motor starts
7) switch in first circuit opens
8) spring retracts the contacts holding them apart

Question 11

what to do to find the direction of the magnetic field

Answer 11

right hand thumb rule

Question 12

find out directions of magnetic field flows on different object

Answer 12

in textbook or folder

Question 13

what to do in order to predict the direction a current carrying conductor or wire will move in an external magnetic field

Answer 13

fleming's left hand rule 
thumb is force 
forefinger is magnetic field (always from north to south)
current is middle finger
do some practice for this

Question 14

look at dc motor parts in

Answer 14

folderrrrr I’m bare tired jheezzz

Question 15

current

Answer 15

flows of electrons

Question 16

split ring communicator

Answer 16

changes the direction of the current

Question 17

brush contacts

Answer 17

made of graphite/carbon

Question 18

battery

Answer 18

converts chemical energy to electrical energy

Question 19

coil

Answer 19

rotates in the permanent magnetic field

Question 20

kinetic energy

Answer 20

moving objects have this

Question 21

permanent magnet

Answer 21

has a north and south pole

Question 22

force on the coil

Answer 22

acts at right angles to the permanent magnetic field

Question 23

magnetic field

Answer 23

flows from north to south

Question 24

dc motor

Answer 24

converts electrical energy into useful kinetic energy

Question 25

8 steps on how a loudspeaker works (diagram in folder)

Answer 25

1) current from the amplifier is an ac, it flows in one direction then the other
2) theres an alternating magnetic field around the coil, its attached to the paper cone
3) coil inside a circular magnet
4) the coils magnetic field and the permanent magnetic field interact producing a force between them
5) as the coil has an ac flowing through it, magnetic field is alternating so the force acting on it also alternates
6) the field, current and forces are all at right angles to each other
7) coil vibrates due to the af, which causes the paper cone to vibrate
8) cones vibration causes variations in air pressure and sets up a longitudinal sound wave