MCQ
881. An ideal gas obeys the law-
PT = nR ̅V
PV=n/R ̅T
PV= nR ̅T
PV= nR ̅/T
882. Unit of temperature in SI unit is—
Celsin
Kelvin
Furenheit
Centigrade
883. 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
884. 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
885. An evaporator is also known as—
cooling coil
freezing coil
chilling cod
all of these
886. The human body feels comfortable who the heat stored in the body is.
positive
zero
negative
none
887. 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
888. In a refrigeration cycle, the flow of refrigerant is controlled by –
compressor
evaporator
expansion valve
condenser
889. Bull bearing is usually made from-
low carbon steel
high carbon steel
chrome steel
medium carbon steel
890. Aqua ammonia is used as refrigerant in the following type of refrigeration system--
compression
indirect
absorption
direct
891. Air refrigeration cycle is used in--
domestic refrigerators
commercial refrigerators
air-conditioning
gas liquefaction
892. The vapour pressure of refrigerant should be—
higher than atmospheric pressure
equal to atmospheric pressure
lower than atmospheric pressure
could be anything
893. At lower temperatures and pressures, the latent heat of vapourisation of a refrigerant-
decreases
increases
remains same
depends on other factors
894. Calorie is a measure of-
Specific heat
Quantity of heat
Thermal capacity
Entropy
895. A diathermic wall is one which-
Prevents thermal interaction
Permits thermal interaction
Encourages thermal interaction
Discourages thermal interaction
896. Total heat of a substance is also known as-
Internal energy
Entropy
Thermal capacity
Enthalpy
897. Accumulators should have adequate volume to store refrigerant charge at least-
10%
50%
25%
75%
898. 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
899. An adiabatic wall is one which-
Prevents thermal interaction
Permits thermal interaction
Encourages thermal interaction
Discourages thermal interaction
900. 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