Question #1bc13

1 Answer
May 16, 2017

The correct answer is b).


Since temperature changes are continuous, we need to use something that changes continuously with the temperature.

a) A metal bar expands (changes its length) as it is heated, so we could use the changing length as a measure of temperature.

b) A liquid that changes colour suddenly at 100 °C would not be very useful.

All it would tell you is when the temperature is 100 °C.

c) According to Gay-Lussac's Pressure Temperature Law, the pressure #p# of a given amount of gas at constant volume is directly proportional to the Kelvin temperature #T#.

#color(blue)(bar(ul(|color(white)(a/a)p = kTcolor(white)(a/a)|)))" "#

Thus, we could use the pressure as a measure of the temperature.

d) Liquid mercury expands as the temperature increases.

Thus, we can use mercury in a thin tube to measure temperature.

Mercury thermometer

As the mercury in the thermometer bulb expands, it moves through a thin capillary graduated in degrees.

The clinical thermometer above shows a temperature of 36.5 °C.