According to Newton's law of cooling, the heat transfer from a hot body to a cold body is

A Directly proportional to the surface area
B Directly proportional to the difference of temperatures between the two bodies
C Either (A) or (B)
D Both (A) and (B)

Correct Answer: Both (A) and (B)

Newton's law of cooling states that the rate of heat loss of a body is directly proportional to the difference in the temperatures between the body and its surroundings.
Bissoy MCQ
#Mechanical Engineering #Heat And Mass Transfer

Related Questions

When heat is transferred from hot body to cold body, in a straight line, without affecting the intervening medium, it is referred as heat transfer by
A Conduction
B Convection
C Radiation
D Conduction and convection
The scales form in heat exchanges after a period of operation and provide additional resistance to heat transfer with some heat transfer coefficient . The reciprocal of this scale heat transfer coefficient is called .
A scaling factor
B forming factor
C resisting factor
D fouling factor
Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the
A Surrounding temperature
B Average temperature of the fin
C Temperature of the fin end
D Constant temperature equal to that of the base
In a heat exchanger, the rate of heat transfer from the hot fluid to the cold fluid
A Varies directly as the area and the LMTD
B Directly proportional to LMTD and inversely proportional to the area
C Varies as square of the area
D None of these
In convection heat transfer from hot flue gases to water tube, even though flow may be turbulent, a laminar flow region (boundary layer of film) exists close to the tube. The heat transfer through this film takes place by
A Convection
B Radiation
C Conduction
D Both convection and conduction
When heat is transferred from one particle of hot body to another by actual motion of the heated particles, it is referred to as heat transfer by
A Conduction
B Convection
C Radiation
D Conduction and convection
For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area
A Increases
B Decreases
C Remains constant
D Passes through a maxima
Stress may be expressed in Newtons
A Per millimetre square (N/mm2)
B Per centimetre square (N/cm2)
C Per metre square (N/m2)
D None of these
The initial tension (in newtons) in a bolt used for making a fluid tight joint like steam engine cover joints, is calculated by the relation (where d = Nominal diameter of bolt in mm)
A 1420 d
B 1680 d
C 2080 d
D 2840 d
Air is to be heated by condensing steam. Two heat exchangers are available (i) a shell and tube heat exchanger and (ii) a finned tube heat exchanger. Tube side heat transfer area are equal in both the cases. The recommended arrangement is
A Finned tube heat exchanger with air inside and steam outside
B Finned tube heat exchanger with air outside and steam inside
C Shell and tube heat exchanger with air inside tubes and steam on shell side
D Shell and tube heat exchanger with air on shell side and steam inside tubes

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