Question

If you were to make a very sensitive glass thermometer, then which of the following working liquids would you choose?

• A. Mercury
• B. Gasoline
• C. Alcohol
• D. Glycerine

Answer 1

The correct option is B

Gasoline

1. A thermometer works on the principle that solids and liquids expand on heating.
2. To make a glass thermometer very sensitive, we need a substance having a very large coefficient of thermal expansion so that for very small changes in temperature, there will be large fluctuations in the volume of liquid.
3. The linear thermal coefficient of given substances at ${20}^{0}C$ are listed below:-

1. Mercury - $61\times {10}^{-6}{}^{0}C^{-1}$
2. Gasoline - $317\times {10}^{-6}{}^{0}C^{-1}$
3. Alcohol - $250\times {10}^{-6}{}^{0}C^{-1}$
4. Glycerine - $160\times {10}^{-6}{}^{0}C^{-1}$

Among given substances, the coefficient of thermal expansion of gasoline is greater than that of other substances.

Hence to make a very sensitive glass thermometer the working liquid should be gasoline. Therefore, option B is correct.