(a) 8.64 Ω
(b) 8.08 Ω
(c) 7.92 Ω
(d) 7.20 Ω
Correct Answer: (a)
Explanation
Rₜ = R₀(1 + αt)
= 8(1 + 0.0008 × 100) = 8.64 Ω
Notes for
More Information
MCQ: Temperature Coefficient of
Resistance
The resistance of a wire
at 0°C is 8 Ω.
The temperature coefficient of resistance is 0.0008 /°C.
Find the resistance at 100°C.
Concept
1. The temperature
coefficient of resistance (α) represents the change in resistance per
degree Celsius.
2. For metallic
conductors, resistance increases with temperature.
3. The
relation between resistance and temperature is:
Formula Used
Where:
= resistance at
temperature 
= resistance at
reference temperature
= temperature
coefficient of resistance
Given Data
4. Resistance
at 0°C:
5. Initial
temperature:
6. Final
temperature:
7. Change in
temperature:
8. Temperature
coefficient:
Calculation
9. Substitute
values in the formula:
10.
Simplifying:
11.
Further:
12.
Final value:
Final Answer
✅ Resistance
at 100°C = 8.64 Ω
Important Exam Notes
13.
Always check units of temperature coefficient (must
be per °C).
14.
Metals have a positive temperature coefficient.
15.
Even a small change in α significantly
affects numerical answers.
16.
Do not confuse 0.0008 with 0.008 (decimal
error).