Mechanical Engineering MCQs

Which of the following statement is correct ?

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A fire tube boiler occupies less space than a water tube boiler, for a given power.
Steam at a high pressure and in large quantities can be produced with a simple vertical boiler.
A simple vertical boiler has one fire tube.
all of the above
✅ The correct answer is option C.

Pre-ignition is caused by the spontantaneous combustion of the mixture before the end of the compression stroke, and is due to

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cylinder walls being too hot
overheated spark plug points
red hot carbon deposits on cylinder walls
any one of these
✅ The correct answer is option D.