Describe an activity to prove that the resistance
of a wire depends on its length, cross-sectional
area and material of the wire.
Answers
Answer
Conductors have resistance, but some are worse than others. The free electrons keep bumping into atoms. A wire's resistance depends on four main factors:
Resistivity
Length of the wire
Cross-sectional area
Temperature of the wire
Explanation
An Investigation Into the Resistance of a Wire - GCSE Physics Coursework
Introduction
In this article I will investigate what affects the resistance of a wire.
Electricity flows in metals. Metal wires are made of millions of tiny metal crystals, and each crystal’s atoms are arranged in a regular pattern. The metal is full of "free" electrons that do not stick to any particular atom; rather, they fill the space between the atoms. When these electrons move, they create an electric current.
Conductors have resistance, but some are worse than others. The free electrons keep bumping into atoms. A wire's resistance depends on four main factors:
Resistivity
Length of the wire
Cross-sectional area
Temperature of the wire
I will investigate how the length of the wire affects the resistance. I have done a preliminary experiment to help me decide the best way to do my investigation. The results will help me make predictions, as well.
Preliminary Investigation
Below are my results from the preliminary experiment . To ensure accuracy, I have taken three readings each of volts and current
Results show that as the length of the wire increases, the resistance increases, as well. Furthermore, if you double the length of the wire, the resistance is roughly doubled. For example, when the length of the wire is 20cm the resistance is 3.14 ohms; when the length of the wire is 40cm the resistance is 6.18 ohms, which is roughly double. In my main investigation I will see if this observation applies to my results.
I found that the apparatus I used was suitable, but I think that I could possibly increase the number of data points to generate more reliable results, perhaps by increasing the length of the wire by 5cm each time, instead of by 10cm.
take two wire of same material and equal
cross section area but differ in length
and connect both with source of equal
then you seen that resistance of wire whose length is large produce more resistance than small wire. x similarly take two wire of same material and equal length but differ in cross section area and connect both with source of equal pd then you concluded that the resistance of wire whose cross section area is bigger has low resistance than other wire.
Take two wire of equal length and Cross section area but differ in material and connect with source of equal pd then you concluded that both has differ resistance.
Hope this will help you .