In the interval between the freezing point (ice point) of water and 700.0deg-C,

Question

In the interval between the freezing point (ice point) of water and 700.0deg-C, a platinum resistance thermometer is to be used for interpolating temperatures from 0 °C to the melting point of zinc, 692.666 K. The temperature, in Celcius or Centigrade, is given by a formula for the variation of the resistance of the thermometer with temperature: R = R,o(1 + A Tc + B Tc2). Ro, A, and B are constants determined by measurements at the ice point, the steam point, and the melting point of zinc. If R equals 12.09800 ohms at the ice point, 81.05660 ohms at the steam point, and 252.73692 ohms at zinc's melting point, find Ro.

What is A?

What is B?

Explanation / Answer

R = R,o(1 + A*Tc + B*Tc^2)

Ice point: 12.09800 =R,o*(1+A*0+B*0) =>R,o=12.09800

steam point: 81.05660=12.09800 *(1+A*100+B*100^2) => 1+100*A+10,000B= 6.7=>100*A+10,000B=5.7----(1)

melting point of zinc:Tc=692.666K=419.666oC

252.73692 =12.09800 (1+A*419.666+B*419.666^2)

=> 1+419.666*A+176119.55*B=20.89

=>419.666*A+176119.55*B=19.89------------------------------(2)

solving 1 &2

A=0.0600047509205 & B=3.0047509205*10^5

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

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