Steam Boilers, Engines, Nozzles and Turbines
The difference between Cornish boiler and Lancashire boiler is that

Former is fire tube type and latter is water tube type boiler
Former is water tube type and latter is fire tube type
None of the listed here
Former contains one fire tube and latter contains two fire tubes

ANSWER DOWNLOAD EXAMIANS APP

Steam Boilers, Engines, Nozzles and Turbines
Spontaneous combustion is a phenomenon in which

Coal bursts into flame without any external ignition source but by itself due to gradual increase in temperature as a result of heat released by combination of oxygen with coal
All the fuel burns instantaneously producing high energy release
Explosion in furnace
Fuel burns with less air

ANSWER DOWNLOAD EXAMIANS APP