Question

One calorie is defined as the eat required to raise the temperature of 1 gm of water by ${{1}^{\circ }}C$ in a certain interval of temperature and at certain pressure. The temperature interval and pressure are?
a)${{13.5}^{\circ }}C\text{ to }{{14.5}^{\circ }}C\text{ }\!\!\And\!\!\text{ }76mm\text{ of Hg}$
b)${{6.5}^{\circ }}C\text{ to }{{7.5}^{\circ }}C\text{ }\!\!\And\!\!\text{ }76mm\text{ of Hg}$
c)${{14.5}^{\circ }}C\text{ to 15}{{.5}^{\circ }}C\text{ }\!\!\And\!\!\text{ }76mm\text{ of Hg}$
d)${{98.5}^{\circ }}C\text{ to 99}{{.5}^{\circ }}C\text{ }\!\!\And\!\!\text{ }76mm\text{ of Hg}$

Answer 1

Hint: One calorie is defined as the amount of heat required to raise the temp of 1 gm of water from ${{14.5}^{\circ }}C\text{ to 15}{{.5}^{\circ }}C\text{ }\!\!\And\!\!\text{ }76mm\text{ of Hg}$

Complete step by step answer:One calorie is equal to approximately 4.2 joules. Since the quantity of heat represented by the calorie varies at different temperatures, it is necessary to define the temperature at which the specific heat of water is to be taken as 1 calorie.
Thus the “15° calorie” (also called the gram-calorie, or small calorie) was defined as the amount of heat that will raise the temperature of 1 gram of water from ${{14.5}^{\circ }}C\text{ to 15}{{.5}^{\circ }}C\text{ }$
Hence, option (c) is the correct answer.

Additional Information:
Also, we have the 20° calorie that will raise the temperature of 1 gram of water from ${{19.5}^{\circ }}C\text{ to 20}{{.5}^{\circ }}C\text{ }$
And the mean calorie, that will raise the temperature of 1 gram of water from ${{0}^{\circ }}C\text{ to }{{100}^{\circ }}C\text{ }$

Note: The calorie is a unit of energy widely used in nutrition.
Calorie relates directly to the metric system, and therefore to the SI system. It is regarded as obsolete within the scientific community, since the adoption of the SI system, but is still in some use.