71401. During a refrigeration cycle, heat is rejected by the refrigerant in a
71402. A refrigeration system
71403. The subcooling in a refrigeration cycle
71404. Which of the following is a non-ferrous metal?
71405. During sensible cooling of air __________ decreases.
71406. The critical radius is the insulation radius at which the resistance to heat flow is
71407. In case of solids, the heat transfer takes place according to radiation.
71408. A water cooled condenser operates at a __________ condensing temperature than an air-cooled condenser.
71409. The relative humidity decreases as air gets wet.
71410. The temperature of ammonia after compression in a vapour compression system is
71411. The centrifugal compressors are generally used for refrigerants that require
71412. The water, alcohol and ammonia have same refrigerating effect at different altitudes.
71413. The automobile radiator is a heat exchanger of
71414. In mechanical refrigeration system, the refrigerant occurs as liquid between condenser and expansion valve.
71415. A heat pump working on a reversed Carnot cycle has a C.O.P. of 5. It works as a refrigerator taking 1 kW of work input. The refrigerating effect will be
71416. The curved lines on a psychrometric chart indicates
71417. During humidification process, __________ increases.
71418. A pressure gauge on the discharge side of a refrigerant compressor reads too high. The reasons will be
71419. The counter-current flow heat exchanger can transfer __________ heat than parallel flow heat exchanger.
71420. The freon group of refrigerants are
71421. For evaporators and condensers, for the given conditions, the logarithmic mean temperature difference (tm) for parallel flow is __________ that for counter flow.
71422. A vapour absorption refrigerator uses __________ as a refrigerant.
71423. Thermal conductivity of air increases with rise in temperature.
71424. The material of pipe lines for a system using ammonia as a refrigerant should be copper.
71425. The wave length corresponding to the maximum energy is inversely proportional to the absolute temperature. This statement is called Planck's law.
71426. Which of the following refrigerant has the highest freezing point.
71427. Air conditioning means
71428. The emissivity for a black body is
71429. Which of the following would lead to a reduction in thermal resistance?
71430. The ratio of the thickness of thermal boundary layer to the thickness of hydrodynamic boundary layer is equal to (Prandtl number)n, where n is equal to
71431. Free convection flow depends on
71432. The critical pressure of a liquid is the pressure
71433. Conduction is a process of heat transfer
71434. Thermal diffusivity of a substance is
71435. Chemical name of chalk is?
71436. Fouling factor is used
71437. The natural convection air cooled condensers are used in
71438. The process, generally used in winter air-conditioning to warm and humidity the air, is called
71439. At 100% relative humidity, wet bulb temperature, dry bulb temperature, dew point temperature and saturation temperature are equal.
71440. Bell-Coleman cycle is a
71441. Sulphur dioxide is extremely toxic and non-flammable.
71442. The transfer of heat from one body to another takes place only when there is a temperature difference between the bodies.
71443. A heat exchanger with heat transfer surface area A and overall heat transfer coefficient U handles two fluids of heat capacities Cmax and Cmin. The number of transfer units (NTU) used in the analysis of heat exchanger is specified as
71444. Which tax is levied and collected by the Union but wholly assigned to the states?
71445. Which of the following statement is correct for ammonia as a refrigerant?
71446. The wet bulb temperature at 100% relative humidity is __________ dew point temperature.
71447. The use of heat exchangers is made in
71448. In a heat exchanger with one fluid evaporating or condensing, the surface area required is least in
71449. Reflection of infrared rays emitted by earth by atmosphere causes?
71450. The horizontal and uniformly spaced lines on a psychrometric chart indicates relative humidity.