MCQ
2121.
pick up incorrect statement-the
lithium bromide used in vapour absorption cycle is nonvolatile
lithium bromide plant can't operate below 0 °C
a separator is used in lithium bromide plant to remove the unwanted water vapour by condensing
concentration of solution coming out of lithium bromide generator is more in comparison to that entering the generator
2122.
In vapour compression cycle, the condition of refrigerant is very wet vapour-.
after passing through the condenser
betore passing through the condenser
after passing through the expansion or throttle valve
before entering the compressor
2123.
Air conditioning means--
heating
cooling
dehumidifying
all of these
2124.
An important characteristic of absorption system of refrigeration is--.
noisy operation
quiet operation
cooling below 0°C
very little power consumption
2125.
When a gas is heated change takes place in.
Pressure
Volume
Temperature
All of these
Himalay Sen Sir
মেকানিক্যাল ইঞ্জিনিয়ারিং MCQ
থার্মোডায়নামিক্স mcq
mechanical mcq
মেকানিক্যাল বিগত সালের প্রশ্ন সমাধান
ব্যাখ্যা: During compression, the volume (V) of a ga decreases. When this happens, the pressure (P) of the gas increases if the number of moles (n) of gas remains constant. If you keep the pressure constant, reducing the temperature (T) also causes the gas to compress .
2126.
In vapour compression cycle, the condition of refrigerant is high pressure saturated liquid-.
after passing through the condenser
before passing through the condenser
after passing through the expansion or throttle valve
before entering the expansion valve
2127.
If a gas vapour is allowed to expand through a very minute aperture, then such a process is known as-
Free expansion
Hyperbolic expansion
Adiabatic expansion
Throttling
2128.
In vapor compression cycle the condition off refrigerant is dry saturated vapour—
after passing through the condenser
before entering the compressor
after passing through the expansion or throttle valve
before passing through the condenser
2129.
Clapeyron equation is applicable for registration at—
saturation point of vapour
saturation point of liquid
sublimation temperature
triple point
2130.
The lower horizontal line of the refrigeration cycle plotted on pressure-enthalpy-diagram represents--
condensation of the refrigerant vapour
evaporation of the refrigerant liquid
compression of the refrigerant vapour
meltering of the refrigerant liquid
2131.
Change in enthalpy of a system is the heat supplied at-
Constant pressure
Constant temperature
Constant volume
Constant entropy
2132.
Mass flow ratio of NH3 in comparison to Freon-12 for same refrigeration load and same temperature limits is of the order of-
1:1
9:1
1:9
1:3
2133.
In vapour compression cycle, the condition of refrigerant is superheated vapour-.
after passing through the condenser
before passing through the condenser
after passing through the expansion or throttle valve
before entering the expansion valve
2134.
The specific heat of air increases with increase in-
Temperature
Pressure
Both pressure and temperature
Variation of its constituents
2135.
Ammonia is-.
non-toxic
non-inflammable
toxic and non-inflammable
highly toxic and inflammable
2136.
A heat exchange process in which the product of pressure and volume Remains constant is known as-
Heat exchange process
Throttling process
Isentropic process
Hyperbolic process
2137.
Freon group of refrigerants are-.
inflammable
toxic
non-inflammable and toxic
non-toxic and non-inflammable
2138.
In vapour compression cycle using NH, as refrigerant, initial charge is filled at-.
suction of compressor
delivery of compressor
high pressure side close to receiver
low pressure side near receiver
2139.
Thermal conductivity of air with rise in temperature-
increases
decreases
remains constant
both increases and decreases
Himalay Sen Sir
মেকানিক্যাল ইঞ্জিনিয়ারিং MCQ
mechanical mcq
মেকানিক্যাল বিগত সালের প্রশ্ন সমাধান
রেফ্রিজারেশন mcq
ব্যাখ্যা: Thermal conductivity of any material is dependent on two things:
i)The motion of free electrons
ii) Lattice vibrations
Thermal conductivity of liquids decreases with increasing temperature as the liquid expands and the molecular move apart.
In the case of solids because of lattice distortings higher temperatures make it difficult for electrons to flow, hence the thermal conductivity of metals decreases at non-metals, electronic conductivity is practically non-existent and due to an increase in phonon conduction, the thermal conductivity increases.
2140.
In vapour compression cycle, the condition of refrigerant is saturated liquid-
after passing through the condenser
after passing through the condenser
after passing through the expansion throttle valve
before entering the expansion valve