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Physics 21st Century > Electric circuits > Flashcards

Flashcards in Electric circuits Deck (94)
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1

What is an atom made up of?

Charged particles, protons and electrons (and neutrons, which don't have a charge)

2

What is the charge on a neutral object?

No overall charge

3

What sort of forces are there between charged objects?

Electrostatic.

4

Like charges do what?

Repel

5

Unlike charges do what?

Attract

6

How does something become charged by rubbing?

The outer electrons are less strongly attracted to the nucleus and can be removed by rubbing

7

What will an objects charge be if it has lost electrons?

+ve

8

What will an object be if it has gained electrons?

-ve

9

What sort of surfaces need to be rubbed together to generate a charge on the objects?

Insulating surfaces - any charge on a radiator, for instance, is passed on the the earth

10

How is lightening believed to be generated?

Charge build up in the clouds due to friction of air/water particles/ice crystals.

11

Why are metals good conductors?

They have free electrons

12

Why are plastic insulators?

There are very few free electrons.

13

If a bulb is lit in a circuit, what do you know about the circuit?

There is an electric current.

14

Where does the energy in a circuit come from?

The moving electrons transfer their energy.

15

Why does electricity flow in a closed circuit?

The electrons are attracted to the positive terminal.

16

What is the flow of charge called?

The current

17

What is the bulb doing?

Converting the energy carried by the electrons to light (and heat) energy

18

What is the definition of the rate of flow of charge?

The current.

19

What is electric current measured in?

Ampères, or Amps

20

How does the current increase?

By putting more energy into the charged particles from the power supply

21

What happens to charge in an electric circuit?

It is conserved.

22

What happens to energy in an electric circuit?

It is transferred.

23

How do you measure current?

An ammeter

24

How is an ammeter connected?

In series

25

How is an ammeter shown in a circuit?

A capital A in a circle.

26

How do you measure voltage?

A voltmeter.

27

How is a voltmeter connected?

In parallel across a component.

28

How is a voltmeter shown in a circuit?

A capital V in a circle.

29

What is the unit of voltage?

The volt.

30

What is the voltage across the power supply a measure of?

How much energy is supplied to the circuit - the difference in energy between the two terminals.