Motor Effect Flashcards Preview

Physics > Motor Effect > Flashcards

Flashcards in Motor Effect Deck (25):
1

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

magnetic field

2

what is an electromagnet

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

3

what is the electromagnet in a circuit

a solenoid with a soft iron core

4

what is a soft magnet

can be magnetised and demagnetised easily

5

what is a hard magnet

hard to magnetise but once done it stays magnetised

6

where is a magnetic field produced on a wire

around a current carrying conductor

7

how can you make the magnetic field in a circuit stronger

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

8

what is the motor effect

converting electrical energy into kinetic energy

9

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

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

10

8 steps for how a battery works in a car

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

11

what to do to find the direction of the magnetic field

right hand thumb rule

12

find out directions of magnetic field flows on different object

in textbook or folder

13

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

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

14

look at dc motor parts in

folderrrrr I'm bare tired jheezzz

15

current

flows of electrons

16

split ring communicator

changes the direction of the current

17

brush contacts

made of graphite/carbon

18

battery

converts chemical energy to electrical energy

19

coil

rotates in the permanent magnetic field

20

kinetic energy

moving objects have this

21

permanent magnet

has a north and south pole

22

force on the coil

acts at right angles to the permanent magnetic field

23

magnetic field

flows from north to south

24

dc motor

converts electrical energy into useful kinetic energy

25

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

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