Question

The calorific value of wood and coal is 20000 kJ/kg and 30000 kJ/kg respectively. Which will produce the most heat? *

Answer 1

$\huge\textrm{Answer :}$

30,000 kJ heat will produce when we burn 1kg of coal. we see same amount of wood and coal produce different amount of heat. heat produced by 1kg of coal is higher than that of wood. so, the largest amount of heat is produced by coal.

Answer 2

Coal will produce the most heat.

• There are calorific values of wood and coal mentioned in the question, which are :

1. Calorific value of wood = 20000 kJ/kg
2. Calorific value of coal = 30000 kJ/kg

• Now, these calorific values actually mean that -

1. Complete combustion of 1kg wood will produce about 20000kJ of heat.
2. Complete combustion of 1kg coal will produce about 30000kJ of heat.

• Now, it is obvious that, 30000kJ > 20000kJ
• Which implies, due to complete combustion in each cases, 1 kilogram of coal will produce more heat than 1 kilogram of wood.
• Hence, coal will produce most heat, in this case.