Question

The energy that helps burning wood is:
A) Chemical
B) Electrical
C) Potential
D) Muscular

Answer 1

Hint: It is a universal fact that energy can neither be destroyed nor can be created but it can always be converted from one form to another form. Generally, one type of energy always gets converted to two or more types of energy, only in ideal cases a complete energy gets totally converted to another form of energy.

Complete solution:
If one heats up a wood at a certain degree of temperature then and then only the wood catches fire or starts to burn. Otherwise, the wood cannot burn, essentially it is heat energy that burns the wood but only heat is not enough to burn the wood, heat needs a medium to burn and that medium is oxygen, without oxygen at a very high temperature the wood may get destroyed but it will not burn. Under the influence of heat, wood produces substances which react eagerly with oxygen and thus leading to the high propensity of wood to ignite and burn.
Ignition and combustion of the wood is due to a process called pyrolysis (thermal decomposition) of the cellulose and the reactions due to pyrolysis release gas in the air which combines with oxygen and at high temperature it starts to burn.

Final answer is option (A) is correct. Therefore, the energy that helps burning wood is chemical in nature.

Note: The decomposition of the wood cellhouse due to thermal decomposition which is caused by heat with combination of oxygen results in an extreme exothermic reaction which in turn when goes out in the air and again mixes with the oxygen it gets ignited and thus the wood starts to burn.