The length of mercury thread when it is at 0°C, 100°C and at an unknown temperature \(\theta\) is 25mm, 225mm and 175mm respectively. The value of \(\theta\) is
85.0oC
80.0oC
75.0oC
70.0oC
Correct answer is C
\(\frac{175 - 25}{225 - 25} = \frac{x - 0}{100 - 0}\)
\(\frac{150}{200} = \frac{x}{100}\)
\(x = \frac{150 \times 100}{200}\)
= 75°C