NEET2023PhysicsCurrent ElectricityActual
The resistance of platinum wire at 0   ° C is 2   Ω and 6 . 8   Ω at 80   ° C . The temperature coefficient of resistance of the wire is:
Options
- A3 × 10 - 1   ° C - 1
- B3 × 10 - 4   ° C - 1
- C3 × 10 - 3   ° C - 1
- D3 × 10 - 2   ° C - 1
Correct answer
D. 3 × 10 - 2   ° C - 1
Step-by-step solution
The variation of resistance of a conducting metal with temperature is given by R T = R 0 1 + α T 2 - T 1       . . . 1 Substitute the values of the known parameters into equation (1) and solve to calculate the required temperature coefficient. 6 . 8   Ω = 2   Ω × 1 + α 80 - 0 °   C ⇒ 1 + 80 α = 3 . 4 ⇒ 80 α = 2 . 4 ⇒ α = 3 × 10 - 2   C - 1