Resistivity | MCQs

Explanation

If two metallic conductors have the same resistivity, they can be differentiated based on their temperature coefficient. 

The temperature coefficient of resistivity indicates how much the resistivity of a material changes with a temperature change.

Materials with the same resistivity can have different temperature coefficients, meaning their resistance will change differently as temperature changes. 

Explanation

Resistivity after cutting a wire in half:

Resistivity 𝜌 is a material property, independent of shape, size, or length.

When a wire is cut, resistance changes, but resistivity remains the same.

Explanation

Resistivity is a measure of how strongly a material opposes the flow of electric current.

Here's a general classification based on resistivity (in Ω-cm):

$10^5$ and 10 ^9 Ω-cm, it is classified as an insulator because it resists the flow of electric current very strongly.

Explanation

At constant temperature, the resistance (R) of a conductor is inversely related to its cross-sectional area (A). This is expressed by the formula: R = ρ × L / A

where:

• R is the resistance
• ρ (rho) is the resistivity of the material
• L is the length of the conductor
• A is the cross-sectional area

As the cross-sectional area (A) increases, the resistance (R) decreases, and vice versa. This is why thicker wires have lower resistance than thinner wires.

Explanation

When the length of a copper wire is doubled, the resistivity remains the same.

Resistivity is an intrinsic property of the material and does not change with the dimensions of the wire.

However, the resistance will double, as resistance is directly proportional to the length of the wire.