Physics - Heat & Thermo Question with Solution | TestHub
Thermometers sometimes contain red or blue liquid, which is often ethanol. What advantages and disadvantages does this have compared to mercury.
Evaluate the following statements.
Statement I: Ethanol has a higher boiling point than mercury and never wets glass.
Statement II: Ethanol has greater expansion and a lower freezing point, but a lower boiling point and can wet glass.
Options:
Answer:
Solution:
Advantages of ethanol: larger expansion coefficient vs , so a longer thread and better sensitivity; freezes at (mercury ), so usable in polar cold; cheap and less toxic than mercury. Disadvantages: boils at 78°C so limited to lower temperatures; colourless (needs dye); wets the glass and can break into drops; poorer conductor, so slower response; less linear expansion. Statement I is false and Statement II true. Correct option: (C).
