2.
Volume of blast furnace slag is about __________ times the volume of hot metal (pig iron) of the same weight

3.
The most commonly used combustion system manufactured in India for the thermal power plant boilers is the __________ combustion system.

7.
If a heat transfer surface is pock-marked with a number of cavities, then as compared to a smooth surface the heat transfer by __________ will not increase.

8.
Pick out the wrong statement.