Understanding Resistivity and Its Measurement

What is the relationship between resistance, length, and area of a wire?

• Resistance is inversely proportional to length and directly proportional to area.

• Resistance is directly proportional to length and inversely proportional to area.

• Resistance is inversely proportional to both length and area.

• Resistance is directly proportional to both length and area.

What is the purpose of the resistor in the experimental circuit?

• To connect the voltmeter in parallel.

• To measure the resistance of the wire.

• To limit the current for safety and prevent overheating.

• To increase the voltage across the wire.

Why is a micrometer screw gauge used to measure the wire's diameter?

• Because it is easier to use than other tools.

• Because it can measure the length of the wire.

• Because the wire's diameter is typically smaller than a millimeter.

• Because it is more accurate than a ruler.

Why are multiple measurements taken along the wire?

• To measure the resistance at different points.

• To calculate the average length of the wire.

• To check for variations in diameter along the wire.

• To ensure the wire is straight.

How is resistance calculated in this experiment?

• By dividing the voltage by the current.

• By subtracting the current from the voltage.

• By multiplying the voltage by the current.

• By adding the voltage and current.

What does the gradient of the resistance vs. length graph represent?

• The voltage across the wire.

• The cross-sectional area of the wire.

• The resistivity of the wire.

• The current through the wire.

What is the formula for the area of a circle used in this experiment?

• Area = π × diameter

• Area = π × diameter^2

• Area = π × radius

• Area = π × (diameter/2)^2

What is a common source of systematic error in this experiment?

• The wire heating up during the experiment.

• The power supply fluctuating.

• The crocodile clip not being at the zero point on the ruler.

• The voltmeter being incorrectly calibrated.

How does a systematic error affect the graph of resistance against length?

• It shifts the graph downwards and changes the slope.

• It shifts the graph upwards without changing the slope.

• It has no effect on the graph.

• It changes the slope of the graph.

Why is it important to keep the wire from heating up during the experiment?

• Because it changes the color of the wire.

• Because it affects the length of the wire.

• Because resistivity is temperature dependent.

• Because the wire might melt.