Electromagnets

Question 1

How does an AC generator work?

Answer 1

as the wire moves through a mag field it cuts field lines
this induces a PD
it’s part of a complete circuit so a current will flow
every half term the induced current changes direction
theRES MORE TO TYHIS ASK SOMEONE ELSE

Question 2

how do microphones work?

Answer 2

sound waves cause diaphragm to vibrate
coil oscillates + cuts mag field lines
pd induced across ends of the coil
part of a complete circuit; current will flow
an AC signal is created as the coil changes direction continuously
frequency of the AC signal is equal to the frequency of the sound wave

Question 3

what do transformers do?

Answer 3

change the PD of an AC power supply?

Question 4

how do transformers work?

Answer 4

-the current in the primary coil produces a mag field
which magnetises iron
-AC in the primary coil-> mag field in iron is AC too
-this INDUCES an alternating PD across the ends of the secondary coil
if the secondary coil is part of a complete circuit a current will flow
and sets up an AC

Question 5

what is the equation for transformers?

Answer 5

pd across coil 1/pd across coil 2 = no of turns on coil 1 / no of turns on coil 2

Question 6

What is the national grid?

Answer 6

a network of cables and transformers that transfer electrical power from power stations to consumers

Question 7

why does the nat grid use the pd/current it does?

Answer 7

to transmit such large amounts of power it either needs a large PD and low current or vice-versa
high current leads to high energy losses, as energy is transferred to surroundings to large pd/low current is used

Question 8

Which transformers do the national grid use?

Answer 8

power station (high current low voltage)
v step up transformer
low current high voltage
V step down transformer
homes (high current low voltage)