Question
Give reason for the following :
Paper by itself catches fire easily where as a piece of paper wrapped around an aluminium pipe does not.
Solution
When paper is heated alone, its ignition temperature is reached quickly due to which it catches fire easily. When the paper wrapped around an aluminium pipe is heated, then the heat supplied to paper is transferred to aluminium pipe by conduction. Due to the continuous transfer of heat from paper to aluminium pipe, the paper does not got heated to its ignition temperature quickly and hence does not catch fire easily.
