Resistance and Resistivity

What is resistivity?

• A measure of how well a material conducts heat.

• A property of a material that quantifies how strongly it resists or conducts electric current.

• The ability of a material to reflect light.

• A measure of a material's density.

How do you calculate resistance?

• Resistance (R) can be calculated using Ohm's Law: V=IR, where V is voltage and I is current.

• Resistance is calculated by dividing voltage by current: R = V/I.

• Resistance is the product of voltage and current: R = V * I.

• Resistance is calculated by adding voltage and current: R = V + I.

What happens to the resistance of a conductor if its length is doubled?

• The resistance remains the same.

• The resistance decreases by half.

• The resistance doubles.

• The resistance quadruples.

What resistance would produce a current of 200 amps with a voltage of 2,000 V?

• 5 ohms

• 10 ohms

• 15 ohms

• 20 ohms

What is the unit of resistivity?

• ohm meter (Ω·m)

• volt (V)

• ampere (A)

• watt (W)

A copper wire of length 2m and area of cross section 1.7 x 10–6 m2 has a resistance of 2 x 10–2 Ω. Calculate the resistivity of copper.

• 1.5 x 10–8 Ω·m

• 1.7 x 10–8 Ω·m

• 2.0 x 10–8 Ω·m

• 1.2 x 10–8 Ω·m

What is the voltage if a resistance of 25 Ω produces a current of 250 amperes?

• 5000 v

• 6250 v

• 7500 v

• 8000 v

How does temperature affect resistivity?

• Resistivity decreases with temperature due to reduced atomic vibrations.

• Resistivity remains constant regardless of temperature changes.

• For most materials, resistivity increases with temperature due to increased collisions between charge carriers and atoms.

• Resistivity increases with temperature only in superconductors.

How do you calculate resistivity?

• ρ = R * A / L

• ρ = R / (A * L)

• ρ = (R * L) / A

• ρ = A / (R * L)

What is resistance?

• A measure of the opposition to the flow of electric current in a conductor.

• The ability of a material to conduct heat.

• The force that pushes electric charges through a circuit.

• A type of electrical energy storage device.