Chapter 23 - Resistance

What happens to the current in a circuit if the voltage is doubled while the resistance remains constant?

• The current is halved.

• The current remains the same.

• The current is doubled.

• The current is quadrupled.

Define Resistance.

• The difference between potential difference and current in a conductor.

• The product of potential difference and current in a conductor.

• The ratio of potential difference to current in a conductor.

• The sum of potential difference and current in a conductor.

What is the SI unit of Resistance?

• Ohm (Ω)

• Ampere (A)

• Watt (W)

• Volt (V)

Define the ohm.

• A conductor has a resistance of 1 Ω if the current through it is 1 A when the pd across it is 1 V.

• A conductor has a resistance of 1 Ω if the current through it is 2 A when the pd across it is 2 V.

• A conductor has a resistance of 1 Ω if the current through it is 0.5 A when the pd across it is 0.5 V.

• A conductor has a resistance of 1 Ω if the current through it is 3 A when the pd across it is 3 V.

State Ohm’s Law.

• Current is directly proportional to Voltage at constant temperature.

• Current is unrelated to Voltage at constant temperature.

• Current is inversely proportional to Voltage at constant temperature.

• Current is equal to Voltage at constant temperature.

What is the shape of the graph for a conductor that obeys Ohm’s Law?

• A straight line passing through the origin.

• A vertical line.

• A curved line passing through the origin.

• A horizontal line.

What is Resistivity?

• The constant ρ given by R = ρl/A for a conductor of length l and cross-sectional area A.

• The resistance of a conductor per unit temperature.

• The resistance of a conductor per unit cross-sectional area.

• The resistance of a conductor per unit length.

What is the SI Unit of Resistivity?

• Ampere (A)

• Ohm metre (Ω m)

• Ohm (Ω)

• Volt (V)

How does the resistance of a metallic conductor change with temperature?

• It decreases as temperature increases.

• It remains constant as temperature increases.

• It increases as temperature increases.

• It fluctuates randomly with temperature changes.

How does the resistance of a thermistor change with temperature?

• It decreases dramatically as temperature increases.

• It fluctuates randomly with temperature changes.

• It increases dramatically as temperature increases.

• It remains constant as temperature increases.