The wire of a platinum resistance thermometer has d resistance of 3.5\(\Omega\) at 0 ^\circC and 10.52\(\Omega\) at 100^\circC. Calculate the temperature of the wire when its resistance is 7.5\(\Omega\).
A
78 °C
B
25 \(^o\)C
C
30\(^o\)C
D
57 \(^o\)C
Verified Correct Answer: D.
Physical Principles & Numerical Solution
Using the formula
t = \(\frac{R - R_0}{R_{(100)} - R_0} \times 100^oC\)
t = \(\frac{7.5 - 3.5}{10.5 - 2..5} \times 100^oC\)
= \(\frac{4}{7} \times 100\)
= 57.14\(^o\)C
~ 57\(^o\)C
Source: Myschool Past Questions Archive (Record #58861)