A spark plug with a black centre insulator indicates

Engine is a device, which converts

A. Mechanical energy into heat energy

B. Heat energy into mechanical energy

C. Mechanical energy into sound energy

D. None of the above

Two-stroke engine is . . . . . . . . engine.

A. Water cooled

B. Air cooled

C. Oil cooled

D. None of these

Engines are:

A. 1 : 4 - 1 : 10

B. 1 : 12 - 1 : 22

C. 3 : 5 - 5 : 10

D. 5: 12 - 5: 22

Another name of diesel engine is

A. High volume combustion engine

B. Low volume combustion engine

C. Constant volume combustion engine

D. No volume combustion engine