Question

A faulty thermometer has its fixed points marked as $3^o$ and ${120}^o$. The temperature of a body measured by the faulty thermometer is ${80}^o$, Find the correct temperature of the body on Celsius scale:

• A. ${36.5}^{o}C$
• B. ${77.8}^{o}C$
• C. ${25.8}^{o}C$
• D. ${66.8}^{o}C$

Answer 1

The correct option is D ${66.8}^{o}C$

Here faulty reading (x)=80
Lower fixed point of faulty reading ( L.F.P)=3
Upper fixed point of faulty reading (U.F.P.)=120
Fundamental interval (F.I.)=120-3=117
Correct reading(C)=?
c/100 = (x-L.F.P)/F.I.
C/100=77/117=0.6681
C=0.6581*100=66.81 celsius scale