Physics 2001 JAMB Past Questions - Question 20: The thermometric substance of an absolute thermometer is

Correct Answer

B

Explanation

An absolute thermometer, also known as an absolute temperature scale, uses a thermometric substance that has a direct and proportional relationship with temperature. The ideal gas, such as helium or hydrogen, is often used as the thermometric substance for an absolute thermometer. These gases obey the ideal gas law, which states that the pressure, volume, and temperature of an ideal gas are related by the equation:

PV = nRT

Where:
P is the pressure of the gas
V is the volume of the gas
n is the number of moles of gas
R is the gas constant
T is the absolute temperature in Kelvin

In an absolute thermometer, the pressure and volume of the gas are measured, and since the gas obeys the ideal gas law, the temperature can be determined directly from these measurements. This makes it suitable for measuring temperature on an absolute temperature scale, such as the Kelvin scale, where temperature is measured relative to absolute zero (0 Kelvin).