GATE 2025 IN – Question 58
The resistance of a thermistor is measured to be 2.25 kΩ at 30 °C and 1.17 kΩ at 60 °C. Its material constant β is ___________ K (rounded off to two decimal places).
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Correct answer: 2160 to 2210
Explanation
The beta model gives ln(R1/R2)=β(1/T1−1/T2).
Convert temperatures to 303.15 and 333.15 K.
Thus β=ln(2250/1170)/(1/303.15−1/333.15)=approximately **2201.43 K**.
Kelvin conversion is essential.