Resistance and Resistivity

Front

What is resistance?

Back

Resistance is a measure of the opposition to the flow of electric current in a conductor.

Front

What is resistivity?

Back

Resistivity is a property of a material that quantifies how strongly it resists or conducts electric current.

Front

How do you calculate resistance?

Back

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

Front

How do you calculate resistivity?

Back

Resistivity (ρ) can be calculated using the formula: ρ = R * A / L, where R is resistance, A is the cross-sectional area, and L is the length of the conductor.

Front

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

Back

6250 v

Front

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

Back

10 ohms

Front

The resistivity of platinoid is 3.3 x 10^-7 ohm meters. Find the resistance of 7.0 m peice of platinoid wire with an average diameter 0.14 cm

Back

1.5 ohm

Front

What is the unit of resistivity?

Back

The unit of resistivity is ohm meter (Ω·m).

Front

How does temperature affect resistivity?

Back

For most materials, resistivity increases with temperature. This is because increased thermal energy causes more collisions between charge carriers and atoms.

Front

What is the relationship between resistance and resistivity?

Back

Resistance (R) is directly proportional to resistivity (ρ) and the length (L) of the conductor, and inversely proportional to its cross-sectional area (A). The formula is R = ρ * L / A.