Fire accidents in coal mines is an example of _______ combustion.
What type of combustion is represented by :
(a) burning of white phosphorus in air at room temperature
(b) burning of LPG in a gas stove ?
(c) ignition of a cracker ?
(d) burning of coal dust in a coal mine ?
Fires in underground coal mines usually occur due to the :
(a) explosive combustion
(b) deliberate combustion
(c) spontaneous combustion
(d) rapid combustion
Spontaneous combustion of coal dust has resulted in many disastrous fires in coal mines.
Geothermal energy is produced by the : (a) fission of radioactive materials (b) burning of coal inside the coal mines (c) combustion of natural gas deep inside the earth (d) fusion of radioactive substances