JAMB - Physics (2007 - No. 8)
A clinical thermometer is different from other mercury in glass thermometers owing to
the constriction on its stem
the grade of mercury used in it
its long stem
its wide range of temperatures
Explication
The constriction in the stem of a clinical thermometer prevents the mercury from returning to the bulb after the temperature has been taken, allowing for a more accurate reading. This feature is what distinguishes it from other types of mercury thermometers, which do not typically have this constriction