11. What will happen when we put petrol in diesel engine?

If we put petrol in diesel engine, there would not be smooth combustion rather detonation that may lead to engine damage.

12. What will happen if we put diesel in petrol engine?

If we use diesel in petrol engine, it will ignite negligible, it will chock engines combustion chamber and leave smoky exhaust.

13. Which is more efficient 4 stroke or 2 stroke engine?

In term of power and torque produced 2 stroke engine is more efficient than 4 stroke engine as it produce same power in half a time.While in terms of fuel consumption 2 stroke engine are less efficient than 4 stroke engine because 2 stroke engines spray the fuel while the exhaust is open which makes a part of air-fuel mixture to exit without being burned. This also makes them more pollutant that 4 stroke engine

14. Why petrol engines compression ratio is low when compared to a diesel engine?

With increase in compression ratio, thermal efficiency of the engine always increase. But in SI engine, the knocking tendency also increase with increase in compression ratio. The reverse is true for CI engine. That’s why, compression ratio is kept low for SI engine as compared to an CI engine.

15. Why there are holes in disc brakes?

For heat dissipation and weight reduction.

16. Why are tyres black?

Due to carbon content.

17. What is critical temperature of a substance?

The critical temperature of a substance is that temperature at and above which vapor of the substance can not be liquefied, no matter how much pressure is applied.

18. What is difference between stress and pressure?

: Pressure represent intensity of external forces acting at a point but stress represent intensity of internal resistant force develop at a point.

: Pressure always act normal to the surface but stress may also act either normal or parallel to the surface.

: Magnitude of pressure at a point in all direction remain same but magnitude of stress at a point in all direction are unequal.

19.  What is the difference between scavenging and supercharging?

: Scavenging is process of flushing out burnt gases from engine cylinder by introducing fresh air in the cylinder before exhaust stroke end.

: Supercharging is the process of supply higher mass of air by compressing the atmospheric air.

20. What is DTSI engine?

Digital Twin Spark Ignition.