A-LEVEL Physics: 5.2.4: Required Practical: Investigating Resistivity (SaveMyExams)

Question 1

What is the Aim of the Required Practical ‘Investigating Resistivity’?

Answer 1

To Determine the Resistivity of a 2m Constant Wire.

Question 2

What are the Variables in the Required Practical ‘Investigating Resistivity’? (4)

Answer 2

-Independent Variable: Length, L, of the Wire (m).

-Dependent Variable: Current, I, through the Wire (A).

-Control Variables:
-Voltage through the Wire (V).
-Material of the Wire.

Question 3

Explain the Method of the Required Practical ‘Investigating Resistivity’: (6)

Answer 3

-Measure the Diameter of the Wire Using a Micrometer.

-Set Up the Circuit. Connect an Ammeter in Series, & a Voltmeter in Parallel to the Wire.

-Attach the Flying Lead to the Test Wire at Lengths of Intervals 0.2m.

-For Each Length, Use a Constant Value of Power Supply.

-Read & Record the Current on the Ammeter for Each Length. Do this 3 Times for Each, & Calculate Average Current.

-Using V=IR, Calculate the Average Resistance for Each Length of Wire.

Question 4

What is the Systematic Error in the Required Practical ‘Investigating Resistivity’?

Answer 4

The End of the Wire that is Attached to the Circuit (Not the Flying Lead that you Attach at Different Length Intervals) Must Start at 0m on the Ruler.
(Otherwise, this could Cause a Zero Error in your Measurements of the Length of the Wire).

Question 5

What are the Random Errors in the Required Practical ‘Investigating Resistivity’? (2)

Answer 5

-Only Allows Small Currents to Flow through the Wire.

-Current Should be Switched Off between Readings, to Keep Temperature Constant.