Question

The resistance of a resistance thermometer has values 2.71 and 3.70 ohm at 10°C and 100°C. The temperature at which the resistance is 3.26 ohm is

• A. 40°C
• B. 50°C
• C. 60°C
• D. 70°C

Answer 1

Answer: (B)

50°C

Answer 2

Change in resistance $3.70 - 2.71 = 0.99\Omega$

corresponds to interval of temperature 90°C.

So change in resistance $3.26 - 2.71 = 0.55\Omega$ Corresponds to change in temperature $= \frac{90}{0.99} \times 0.55 = 50{^\circ}C$