Assertion (A): Bending a wire does not affect electrical resistance.
Reason (R): Resistance of wire is proportional to resistivity of material.
Answer:
Resistance of wire, R = ρ (l / A) —----(i)
Where,
- ρ is the resistivity
- l is the length of the wire.
- A is the area of cross-section of the wire.
When a wire is bent,
- Resistivity - doesn’t change
- Length - doesn’t change
- Area of cross-section - doesn’t change.
Hence, bending a wire does not affect the resistance of a wire.
From equation (i), it is clear that Resistance is directly proportional to resistivity.
Thus,
- Assertion is true.
- Reasoning is true.
So, the correct answer is (a).