NDA2025General AbilityGeneral ScienceActual
Which one of the following instruments can be used to measure −250°C temperature?
Options
- ABy using a mercury based thermometer
- BBy using an alcohol based thermometer
- CBy using a clinical thermometer
- DBy using thermocouple based thermometer
Correct answer
D. By using thermocouple based thermometer
Step-by-step solution
Mercury freezes at -39^ C , so a mercury-based thermometer cannot be used to measure -250^ C . Alcohol freezes at -115^ C , so an alcohol-based thermometer is also unsuitable for measuring -250^ C . A clinical thermometer is designed to measure human body temperature, typically in the narrow range of 35^ C to 42^ C . A thermocouple-based thermometer can measure a very wide range of temperatures, typically from -270^ C to over 2000^ C depending on the metals used. Therefore, it can be used to measure -250^ C . Answe