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রেফ্রিজারেশন এন্ড এয়ারকন্ডিশনিং MCQ
1. 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
2. Thermal conductivity of air with rise in temperature-
increases
decreases
remains constant
both increases and decreases
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.
3. The wet bulb temperature at 100% relative humidity is-- dew point temperature.
Same as
Higher than
Lower than
none
4. Freon group of refrigerants are-.
inflammable
toxic
non-inflammable and toxic
non-toxic and non-inflammable
5. মধ্যবর্তী মাধ্যমের বিচ্যুতি গরম বস্তু হতে ঠান্ডা বস্তুতে সরল রেখার হিট ট্রান্সফার প্রক্রিয়াকে কী বলে?
কনডাকশন
রেডিয়েশন
কনভেকশন
একটিও না
6. 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
7. 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
8. Ammonia is-.
non-toxic
non-inflammable
toxic and non-inflammable
highly toxic and inflammable
9. The COP of a domestic refrigerator in comparison to domestic air conditioner will be --
same
less
more
unpredictable
10. তরল ও বায়বীয় পদার্থের ক্ষেত্রে হিট ট্রান্সফার সংঘটিত হয় যে উপায়ে, তাকে কী বলে?
কনডাকশন
কনভেকশন
রেডিয়েশন
কোনোটিই নয়
11. The evolution of heat of solution takes place in ammonia absorption plant when--
ammonia vapour goes into solution
ammonia vapour is driven out of solution
lithium bromide mixes with ammonia
weak solution mixes with strong solution
12. The vapour compression refrigeratór employs the following cycle-.
Rankine
Carnot
Reversed Carnot
Reversed Rankine
13. An important characteristic of absorption system of refrigeration is--.
noisy operation
quiet operation
cooling below 0°C
very little power consumption
14. 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
15. The COP of a vapor compression plant in comparison to vapor absorption plant is-
more
same
less
unpredictable
16. 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
17. The moisture in None of these refrigerant is removed by-
evaporator
denumidifier
driers
safety relief valve
18. 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
19. 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
20. Clapeyron equation is a relation between-
temperature, pressure specific volur and enthalpy
temperature, pressure and enthalpy
specific volume and enthalpy
temperature and enthalpy