P2.3

Question 1

static electricity

Answer 1

it is when charge builds up in one placwe and it often ends up in a spark when it moves.When you rub two different insulating materials against each other they become electrically charged. This only works for insulated objects. Electrical charges move easily to earth through conductors such as metals.

Question 2

explain what happens when two materials rub against each other

Answer 2

v===Negatively charged particles called electrons move from one material to the other
==The material that loses electrons becomes positively charged
===The material that gains electrons becomes negatively charged
===Both materials gain an equal amount of charge, but the charges are opposite
===only electrons move never the positive charges

Question 3

Detecting charge

Answer 3

==Two charged objects will repel each other if they have the same type of charge
===attract if they are opposite

Question 4

electric current

Answer 4

electric current is a flow of electric charge. No current can flow if the circuit is broken - for example, when a switch is open

Question 5

Measuring current

Answer 5

Current is measured in amperes (which is often abbreviated to amps or A).

Question 6

Calculating current

Answer 6

I = Q ÷ t
I is the current in amperes (amps), A
Q is the charge in coulombs, C
t is the time in seconds, s

Question 7

A potential difference

Answer 7

A potential difference, also called voltage, across an electrical component is needed to make a current flow through it. Cells or batteries often provide the potential difference needed.

Question 8

Calculating potential difference

Answer 8

V = W ÷ Q
V is the potential difference in volts, V
W is the work done (energy transferred) in joules, J
Q is the charge in coulombs, C

Question 9

Cells and circuits

what happens to the potential difference and current when the number of cells in a circuit is changed.

Answer 9

Current
When more cells are connected in series in a circuit, they produce a bigger potential difference across its components. More current flows through the components as a result.
-====cells are connected in series in the same direction, the total potential difference is 3.0 V. If two 1.5V cells are connected in series, but in opposite directions, the total potential difference is 0V, so no current will flow.