Mechanical Engineering Mcqs

Aqua ammonia is used as refrigerant in the following type of refrigeration system_________________?

(A) compression
(B) direct
(C) indirect
(D) absorption
(E) none of the above

Submitted By :Ali Uppal

Efficiency of a Carnot engine is given as 80%. If the- cycle direction be reversed, what will be the value of COP of reversed Carnot cycle_________________?

(A) 1.25
(B) 0.8
(C) 0.5
(D) 0.25
(E) none of the above

Submitted By :Ali Uppal

In vapor compression refrigeration system, refrigerant occurs as liquid between_________________?

(A) condenser and expansion valve
(B) compressor and evaporator
(C) expansion valve and evaporator
(D) compressor and condenser
(E) none of the above

Submitted By :Ali Uppal

A refrigeration cycle operates between condenser temperature of + 27°C and evaporator temperature of- 23°C. The Cannot coefficient of performance of cycle will be_________________?

(A) 0.2
(B) 1.2
(C) 5
(D) 6
(E) 10

Submitted By :Ali Uppal

Accumulators should have adequate volume to store refrigerant charge at least_________________?

(A) 10%
(B) 25%
(C) 50%
(D) 75%
(E) 100%

Submitted By :Ali Uppal

In a flooded evaporator refrigerator, an accumulator at suction of compressor is used to___________________?

(A) collect liquid refrigerant and prevent it from going to compressor
(B) detect liquid in vapour
(C) superheat the vapour
(D) collect vapours
(E) increase refrigeration effect

Submitted By :Ali Uppal

In refrigerators, the temperature difference between the evaporating refrigerant and the medium being cooled should be_________________?

(A) high, of the order of 25°
(B) as low as possible (3 to 11°C)
(C) zero
(D) any value
(E) none of the above

Submitted By :Ali Uppal

Condensing temperature in a refrigerator is the temperature_________________?

(A) of cooling medium
(B) of freezing zone
(C) of evaporator
(D) at which refrigerant gas becomes liquid
(E) condensing temperature of ice

Submitted By :Ali Uppal

The value of COP in vapour compression cycle is usually__________________?

(A) always less than unity
(B) always more than unity
(C) equal to unity
(D) any one of the above
(E) none of the above

Submitted By :Ali Uppal

The C.O.P of a refrigeration cycle with increase in evaporator temperature, keeping condenser temperature constant, will______________________?

(A) increase
(B) decrease
(C) remain unaffected
(D) may increase or decrease depending on the type of refrigerant used
(E) unpredictable

Submitted By :Ali Uppal

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