A resistance thermometer, which measures temperature by measuring the change in

Question

A resistance thermometer, which measures temperature by measuring the change in resistance of a conductor, is made of platinum and has a resistance of 50.0 at 20.0°C.

(a) When the device is immersed in a vessel containing melting indium, its resistance increases to 76.8 . From this information, find the melting point of indium. °C

(b) The indium is heated further until it reaches a temperature of 255°C. What is the ratio of the new current in the platinum to the current Imp at the melting point?

Explanation / Answer

a)

Resistance Variation with temperature is given by

R=Ro[1+alpha*(T-To)]

76.8 =50[1+(3.92*10-3)(T-20)]

T=156.73oC

b)

SInce R=V/I

=>V/I =(V/Io)[1+alpha*(T2-T1)]

I/Io =1/[1+(3.92*10-3)(255-156.73)]

I/Io=0.722

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.