Chapter 4: Current and electricity

Question 1

What is potential difference measured in?

Answer 1

Volts

Question 2

What is current measured in?

Answer 2

Amps

Question 3

What does a resistor do?

Answer 3

Lowers current

Question 4

What is resistance measured in?

Answer 4

Ohms

Question 5

What does a diode do?

Answer 5

Stop current going in one direction

Question 6

What is a coulomb?

Answer 6

The amount of charge in a specific number of electrons

Question 7

What is current relating to coulombs?

Answer 7

The amount of coulombs per second

Question 8

What is 1 amp?

Answer 8

1 coulomb of electrons passing a certain point every second

Question 9

How to work out current:

Answer 9

Current = Charge (coulombs) / Time

Question 10

What is potential difference?

Answer 10

Energy transferred by each coulomb of charge to a component

Question 11

How to work out potential difference?

Answer 11

Volts = Work done / Charge

Question 12

What relationship do current and potential difference have to each other?

Answer 12

Directly proportional

Question 13

How do you work out Potential difference from current and resistance

Answer 13

Pot. diff = Current X Resistance

Question 14

How do you work out resistance in a series circuit?

Answer 14

The resistance of all the components added up.

Question 15

How do you work out the potential difference across a component in a series circuit?

Answer 15

The Pot. diff of all the cells combined given out by the ratio of the power ratings of the components combined

Question 16

How to work out current in a parallel circuit?

Answer 16

V= I x R

Question 17

Why does temperature increase the resistance of a component?

Answer 17

The atoms vibrate more, therefore the electrons which are flowing through collide with the ions more frequently.