Question

A platinum resistance thermometer has a resistance of 200 Ω when placed in an ice 0◦C bath and 232.6 Ω when immersed in a crucible containing a melting substance. What is the melting point of the substance? The temperature coefficient of the platinum is 0.00392 (◦C)−1 . The resistor was calibrated at a temperature of 20◦C. Answer in units of ◦C.

Answer 1

here,

resistance , R0 = 200 ohm , initial temp , Ti = 0 degree C

R = 232.6 ohm

let the melting point be Tf

alpha = 0.00392 degree C^-1

R = R0 *( 1 + alpha * ( delta T))

231.6 = 200 * ( 1 + 0.00392 * (Tf - 0 )

Tf = 40.31 degree C

the melting point of the substance is 40.31 degree C