Practical 7 - Determination of the resistivity of a wire

Question 1

What do we put along the x-axis of our graph?

Answer 1

Length

Question 2

What do we put along the y-axis of our graph?

Answer 2

Resistance

Question 3

What is the gradient that we have on our length v.s Resistivity graph?

Answer 3

ρ/A

Question 4

How do we calculate the resistivity of our wire?

Answer 4

ρ = gradient x A

Question 5

Draw and label the set-up for this practical

Answer 5

(See notes)

Question 6

Resolution of vernier calipers

Answer 6

+-0.01mm

Question 7

Describe the method for this practical

Answer 7

Leave 1 crocodile clip fixed at 1 end of th wire
Move the other clip along a 10cm intervals to cover the whole range
Note voltmeter and ammeter readings each time
Determine resistance using R = V/I
Determine diameter of wire using vernier callipers and determine the cross sectional area form this
Plot the graph
Calculate resistivity

Question 8

How do we calculate the cross-sectional are of the wire?

Answer 8

Pi x r^2

Question 9

How do we measure the diameter of the wire and why?

Answer 9

In 3 different places as it’s a malleable material and therefore could have different diameters in different places

Question 10

What’s the symbol for a mean diammeter?

Answer 10

d with a line on the top