One calorie is the quantity of heat that raises the temperature of

1 gram of water by 1°C

Explanation:

Calorie is a unit of energy and one calorie is defined as -

"The total amount of heat energy that is required in order to increase the temperature of 1 gram of water by 1°C or 1 K at 1 ATM pressure is known as 1 calorie."

It is widely used unit of heat in the field of nutritional science.

Joule is the SI unit of heat energy and mathematically the relation between joule and calorie is -

1 cal = 4.184 joule.