One calorie of heat energy is equivalent to approximately ______ joules of mechanical energy.
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 4.2.
- The calorie was initially defined as the amount of heat necessary at 1 standard atmosphere to increase the temperature of 1 gramme of water by 1º Celsius.
- Since 1925, this calorie has been defined in units of joules, with one calorie equal to about 4.2 joules as of 1948.