Heat Question and Answer – Page 9

The SI (International System of Units) unit of heat is the Joule (J), named after physicist James Prescott Joule. Option A (Calorie) is incorrect — calorie is the CGS unit of heat, not the SI unit. 1 calorie = 4.186 joules. Option B (Joule) is CORRECT — it is the internationally accepted SI unit for measuring heat energy. Option C (BTU) is incorrect — BTU stands for British Thermal Unit, used mainly in engineering and is not an SI unit. 1 BTU = 252 calories. Option D (Kelvin) is incorrect — Kelvin is the SI unit of temperature, not heat. Heat and temperature are different physical quantities. Heat is a form of energy (measured in joules), while temperature is a measure of hotness (measured in Kelvin or Celsius).