Mechanical Engineering Mcqs

In a cycle, the spark lasts roughly for ____________________?

(A) 1 sec

(B) 0.1 sec

(C) 0.01 sec

(D) 0.001 sec

(D) 0.0001 sec

Submitted By: Ali Uppal


A diesel engine as compared to petrol engine (both running ar rated load) is ____________________?

(A) more efficient

(B) less efficient

(C) equally efficient

(D) unperdictable

(D) other factors will decide it

Submitted By: Ali Uppal


Most high speed compression engines operate on ___________________?

(A) Otto cycle

(B) Diesel cycle

(C) Dual cycle

(D) Carnot cycle

(D) Two stroke cycle

Submitted By: Ali Uppal


The cam shaft of a four stroke I.C. engine running at 1500 rmp will run at __________________?

(A) 1500 rpm

(B) 750 rpm

(C) 3000 rpm

(D) any value independent of engine speed

(D) none of the above

Submitted By: Ali Uppal


The term scavenging is generally associated with______________________?

(A) 2-stroke cycle engines

(B) 4-stroke cycle engines

(C) aeroplane engines

(D) diesel engines

(D) high efficiency engines

Submitted By: Ali Uppal


Fuel consumption of diesef engines is not guaranteed at one quarter load because at such low loads________________?

(A) the friction is high

(B) the friction is unpredictable

(C) the small difference in cooling water temperature or in internal friction has a disproportionate effect

(D) the engine is rarely operated

(D) none of the above

Submitted By: Ali Uppal


A diesel engine has_________________?

(A) 1 valve

(B) 2 valves

(C) 3 valves

(D) 4 valves

(D) no valve

Submitted By: Ali Uppal


Diesel engine can work on very lean air fuel ratio of the order of 30 : 1. A petrol engine can also work on such a lean ratio provided__________________?

(A) it is properly designed

(B) best quality fuel is used

(C) can not work as it is impossible

(D) flywheel size is proper

(D) engine cooling is stopped

Submitted By: Ali Uppal


A hmh flame speed is obtained in diesel engine when air fuel ratio is_______________?

(A) uniform throughout the mixture

(B) chemically correct mixture

(C) about 3-5% rich mixture

(D) about 10% rich mixture

(D) about 10% lean mixture

Submitted By: Ali Uppal


Volatility of diesel fuel oil is_________________?

(A) minimum temperature to which oil is heated in order to give off inflammable vapours in sufficient quantity to ignite momentarily when brought in contact with a flame

(B) temperature at which it solidifies or congeals

(C) it catches fire without external aid

(D) indicated by 90% distillation temperature, i.e., when 90% of sample oil has distilled off

(D) temperature at which it flows easily

Submitted By: Ali Uppal