The process of heat transfer from a hot body to a cold body, in a straight line,

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Question
The process of heat transfer from a hot body to a cold body, in a straight line, without affecting the intervening medium, is called radiation.
Options
A. True
B. False

Correct Answer

True

Heat Transfer, Refrigeration and Air Conditioning problems

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1. Fourier's law of heat conduction is (where Q = Amount of heat flow through the body in unit time, A = Surface area of heat flow, taken at right angles to the direction of heat flow, dT = Temperature difference on the two faces of the body, dx = Thickness of the body, through which the heat flows, taken along the direction of heat flow, and k = Thermal conductivity of the body)
Options
A.
B.
C.
D.

3. Degree of saturation or percentage humidity is
Options
A. the mass of water vapour present in 1 m³ of dry air
B. the mass of water vapour present in 1 kg of dry air
C. the ratio of the actual mass of water vapour in a unit mass of dry air to the mass of water vapour in the same mass of dry air when it is saturated at the same temperature and pressure.
D. the ratio of actual mass of water vapour in a given volume of moist air to the mass of water vapour in the same volume of saturated air at the same temperature and pressure

6. The by-pass factor for a cooling coil
Options
A. increases with increase in velocity of air passing through it
B. decreases with increase in velocity of air passing through it
C. remains unchanged with increase in velocity of air passing through it
D. may increase or decrease with increase in velocity of air passing through it depending upon the condition of air entering

7. The formation of frost on cooling coils in a refrigerator
Options
A. increases heat transfer
B. improves C.O.P. of the system
C. increases power consumption
D. reduces power consumption

8. The sensible heat factor during cooling and dehumidification process is given by (where h₁ = Enthalpy of air entering the cooling coil, h₂ = Enthalpy of air leaving the cooling coil, and h_A = Enthalpy of air at the end of dehumidification process)
Options
A.
B.
C.
D.

9. The optimum effective temperature for human comfort is
Options
A. higher in winter than in summer
B. lower in winter than in summer
C. same in winter and summer
D. not dependent on season

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