MCQ
881. An evaporator is also known as—
cooling coil
freezing coil
chilling cod
all of these
882. An adiabatic wall is one which-
Prevents thermal interaction
Permits thermal interaction
Encourages thermal interaction
Discourages thermal interaction
883. A diathermic wall is one which-
Prevents thermal interaction
Permits thermal interaction
Encourages thermal interaction
Discourages thermal interaction
884. A certain refrigerating system has a normal operating suction pressure of 10 kg/cm gauge and condensing pressure of about 67kg/cm The refrigerant used is--
Ammonia
Carbon dioxide
Freon
Brine
885. Accumulators should have adequate volume to store refrigerant charge at least-
10%
50%
25%
75%
886. Total heat of a substance is also known as-
Internal energy
Entropy
Thermal capacity
Enthalpy
887. The human body feels comfortable who the heat stored in the body is.
positive
zero
negative
none
888. Calorie is a measure of-
Specific heat
Quantity of heat
Thermal capacity
Entropy
889. In a refrigeration cycle, the flow of refrigerant is controlled by –
compressor
evaporator
expansion valve
condenser
890. Unit of temperature in SI unit is—
Celsin
Kelvin
Furenheit
Centigrade
891. Bull bearing is usually made from-
low carbon steel
high carbon steel
chrome steel
medium carbon steel
892. Aqua ammonia is used as refrigerant in the following type of refrigeration system--
compression
indirect
absorption
direct
893. At lower temperatures and pressures, the latent heat of vapourisation of a refrigerant-
decreases
increases
remains same
depends on other factors
894. If heat be exchanged in a reversible manner, which of the following property of the working substance will change accordingly?
Temperature
Enthalpy
Internal energy
Entropy
895. The value of COP in vapour compression cycle is usually--
always less than unity
always more than unity.
equal to unity
any one of the above
896. An ideal gas obeys the law-
PT = nR ̅V
PV=n/R ̅T
PV= nR ̅T
PV= nR ̅/T
897. The vapour pressure of refrigerant should be—
higher than atmospheric pressure
equal to atmospheric pressure
lower than atmospheric pressure
could be anything
898. Air refrigeration cycle is used in--
domestic refrigerators
commercial refrigerators
air-conditioning
gas liquefaction
899. In a flooded evaporator refrigerator, an accumulator at suction of compressor is used to--
collect liquid refrigerant and prevent it from going to compressor
detect liquid in vapour
superheat the vapour
collect vapours
900. Addition of heat at constant pressure to a gas results in-
Raising its temperature
Raising its pressure
Raising its volume
Raising its temperature and doing external work