FAQs on Resistance & Resistivity

Question 1

1. What is resistance?

Accepted Answer

Ans. Resistance is the property of a material that opposes the flow of electric current. It is measured in ohms and is denoted by the symbol 'R'. Resistance is responsible for transforming electrical energy into heat energy.

Question 2

2. How is resistance calculated?

Accepted Answer

Ans. Resistance can be calculated using Ohm's Law, which states that resistance is equal to the voltage across a component divided by the current flowing through it. Mathematically, resistance (R) = voltage (V) / current (I).

Question 3

3. What is resistivity?

Accepted Answer

Ans. Resistivity is a measure of a material's resistance to electric current flow. It is an intrinsic property that depends on the material's composition and temperature. Resistivity is denoted by the symbol 'ρ' and is measured in ohm-meters (Ω·m).

Question 4

4. How is resistivity related to resistance?

Accepted Answer

Ans. The resistance of a material is directly proportional to its resistivity. The resistance (R) of a uniform conductor can be calculated using the formula R = (ρ * L) / A, where ρ is the resistivity, L is the length of the conductor, and A is its cross-sectional area.

Question 5

5. What factors affect resistance and resistivity?

Accepted Answer

Ans. The resistance of a material depends on its length, cross-sectional area, and resistivity. Longer conductors have higher resistance, while wider conductors have lower resistance. Additionally, materials with higher resistivity offer greater opposition to current flow, resulting in higher resistance. Temperature also affects resistance, as most conductors increase their resistance with increasing temperature.

Resistance & Resistivity Video Lecture - Physics - Grade 9

Physics

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