# To Investigate how the thickness of a wire affects its Resistance.

Physic’s Coursework

Richard Carragher, S2D

## AIM: To Investigate how the thickness of a wire affects its Resistance.

Background Knowledge.

The electrical supply can be quite easily compared to the water supply we all have in our homes for our heating. The battery can be easily compared to a water pump as they both have to push a flow around a circuit. A resistor can also easily be compared to a water flow constrictor, both slowing down the flow and power of the push.

If the voltage is increased the current is increased.

If you increase the resistance the current is decreased.

##### CHARGE = CURRENT x TIME

Q = I x T

The current I with a value ampere, 1A is the number of charges flowing past a point every second. Charge Q is measured in Coulombs, C.

Short Circuit:

A short circuit happens when the current in a circuit travels along the easiest path it can find. The easiest path is always the one with the least resistance.

Measuring Current & Voltage:

When you have an analogue meter you have to make sure you look at it correctly, you do this by making sure you look at it at exact right angles. You know this when you cannot see the needle reflecting in the mirror of the ammeter. This is to make sure your readings are accurate.

If you are using a digital meter you have to connect the red wire to the red terminal and the black wire to the black terminal.

An ammeter is always connected in series with the test component where a voltmeter is connected in parallel.

SERIES:

PARALLEL:

SERIES:

###### MEASURING VOLTAGE WITH A VOLTMETER

Electrical Energy:

Electrical energy changes in a circuit but it is not used up or destroyed. Electrons have less electrical energy returning to a battery.

CURRENT IS NOT USED UP

SERIES:

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