Question

1 calorie is equal to __________________ joule.

Answer 1

Hint: First find out what is calorie and joule. Conclude that they are the units of the same quantity, yet they convey different information or meaning. Obtain the relationship between calories and joule. State the scenario where these units are used.

Complete step by step solution:
The capacity to do work is called energy. The energy is measured using the number of units. Calorie and Joule are two of them in which energy can be measured. These units, calorie and joule are in proportion. Therefore, any change in Calorie will change its equivalent value in Joules or vice versa. Since calorie and joule are in proportion, their ratio is a constant and it is a fixed number. The relation between calorie and joule is given as 1 calorie = 4.2 joules.
Definition of 1 calorie:
1 calorie is defined as the amount of energy in the form of heat required to raise the temperature of 1 gram of water by${{1}^{{}^\circ }}C$.
Definition of 1 joule:
1 joule is defined as the work done (energy transferred) on an object when a force of 1 N acts on it and the object is moved by 1m in the direction of the force.

Note: Note that even though calorie and joules are the units of the same quantity, they convey different information to us. The unit calorie is used when we deal with energy (or energy transferred) in the form of heat while the unit joule is used when we deal with energy (or energy transferred) in the form of work done. We can also write \[\text{ }\!\!~\!\!\text{ 1 joule = 0}\text{.238 calories}\]