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Flashcards in Electro-magnetic Induction Deck (18):
1

what do motors do in terms of energy

convert electrical --> kinetic

2

what do generators do in terms of energy while using electromagnetic induction

convert kinetic --> electrical

3

how does a generator work

- current induced in a wire
- wire cuts through magnetic field lines
- use method of induction to generate electrical energy from chemical energy

4

how can a generator use electromagnetic induction to induce a larger current

- more powerful/stronger magnet with more magnetic fields
- use a coil around the magnet / a wire with lots of turns/ or many thin wires
- use more kinetic energy at the start to cut through the magnetic field lines to have the output of more KE

5

what is another way of current being produced instead of passing the wire by a magnet

if there is a changing magnetic field from the wire current can be induced -- this is done by an alternating current (transformers use this method)

6

what is the equation to represent the relationship between number of turns in the coil to voltage

N1/N2 = V1/V2

7

what is the purpose of a step-up transformer

so that voltage is increased

8

what is the purpose of raising the voltage of the national grid to around 400kV

to decrease the current while transporting in the national grid so not much heat is lost through the wires resistance

9

what does a step up transformer look like

when there are less turns in the coil on the first half of the magnet than there are on the second

10

what is the equation that assumes a transformer is 100% efficient

power input = power output
OR
I1V1 = I2V2

11

EXPLAIN HOW A STEP UP TRANSFORMEER WORKS

using the key terms: primary, coil, secondary, flux, a.c., input, output, varying, core

12

what is the benefit of the transformer's core being made up of soft iron

so the magnetism of the metal can be switched on and off i.e. it is an electromagnet --> easily magnetised and demagnetised

13

what is the benefit of the transformer's core being laminated

reduces eddy current so this reduces heat loss therefore more efficient

14

what is the equation that links the primary voltage, secondary voltage, primary coil turns and secondary coil turns

V1N1 = V2N2

15

standard magnetic field

goes from the north into the south

16

what is the dynamo effect

using electromagnetic induction to transform kinetic energy into electrical energy

17

two way you can get EM induction

1) an electrical conductor (coil of wire) moving through a magnetic field
2) the magnetic field through an electrical conductor changes (bigger, smaller, reverses)

18

how to test the dynamo effect

connect an ammeter to a conductor and move the conductor through a magnetic field or vice versa and the ammeter will show the magnitude and direction of the induced current