Question

Assertion: At high-temperature, metal wires have a greater chance of short-circuiting

Reason: Both resistance and resistivity vary with temperature.

Is reason correct explanation of the assertion?

• A. Both A and R are true and R is the correct explanation
• B. A is true but R is false
• C. Both A and R are false
• D. Both A and R are true but R is not the correct explanation

Answer 1

The correct option is D

Both A and R are true but R is not the correct explanation

Explanation for the assertion statement:

1. Metal wires are more likely to short-circuit at high temperatures because the flow of electrons increases with temperature.
2. The increase in flow causes more heat dissipation, which melts wire insulation and can produce a short circuit in the cable.

Explanation for the reason statement:

1. The resistance and resistivity of metal wire change with temperature.
2. Resistance is the property of a substance that opposes current flow through it, and the resistance of a conductor is directly proportional to temperature.
3. While resistivity is an intrinsic property, it is not affected by size or shape, but it is affected by temperature in the case of metals, as it increases with increasing temperature.

Therefore, both the statements given are correct but the reason is not the correct explanation of the assertion.

Hence, option D is the correct answer.