Question

Which of the following is not an example of spontaneous combustion ?

(a)
Burning of liquified petroleum gas

(b)
Fire caused in coal mines

(c)
Dry white phosphorous liberates white fumes on exposure to air

(d)
All of these

Answer 1

I would say that A is the right answer, but I wouldn't consider a fire caused in a coal mine to be spontaneous. There is usually an ignition source present that ignites the fine dust particles.

Answer 2

So what should I select?

Answer 3

C

Answer 4

What is the area of a right angle triangle with its hypotenuse and perimeter equal to x and y respectively?