Mains Electricity&In the home Flashcards Preview

Physics > Mains Electricity&In the home > Flashcards

Flashcards in Mains Electricity&In the home Deck (16):
1

Mains supply is DC/AC ?

battery supply is DC/AC?

Mains supply is AC

Battery supply is DC

2

What is the U.K.'s main supply in volts and frequency?

Volts= 230 V

Frequency = 50Hz

3

What does an AC supply mean?

An supply means the current is constantly changing direction

4

What does DC supply mean?

This means that the current always flows in the same direction

5

If you plug in AC supply into an oscilloscope what trace will be shown on the screen?

The screen shows how the voltage of the supply changes with time. The trace goes up and down in a regular pattern.

6

If you plug a DC supply into an oscilloscope what trace will this show?

The trace you get is just a straight line

7

How do you work out the frequency?

Frequency= 1
________

Time period (s)

8

What is electric current?

Electric current is the movement of charge carriers

9

What colours are the neutral wire live wire and earth wire?

Earth wire = green&yellow

Neutral wire= blue

Live wire = brown

10

What is the earth wire used to do?

The earth wire is for protecting the wiring and for safety- it works together with a fuse to prevent fire and shocks

11

How does the earth wire prevent fire and shocks?

It is attached to the metal casing of the appliance and carries the electricity to the earth , away from you

12

Why are the metal parts of a plug made of copper or brass?

Because these are very good conductors

13

Why is the case, cable grip and cable installation in a socket made out of rubber or plastic?

Because these are really good insulators and flexible

14

Which of the live, neutral or earth wires is always at O volts?

The neutral wire( blue)

15

Which two wires usually carry the same current?

The live and neutral wires

16

What will happen to the CRO trace if the voltage of the supplies reduced?

The amplitude of the wave will be decreased so the peaks and troughs will be smaller