61. Fourier's law of heat conduction is valid for
(a) one dimensional cases only
(b) two dimensional cases only
(c) three dimensional cases only
(d) regular surfaces having non-uniform temperature gradients
(e) irregular surfaces.
Ans: a
62. According of Kirchhoff law,
(a) radiant heat is proportional to fourth power of absolute temperature
(b) emissive power depends on temperature
(c) emissive power and absorptivity are constant for all bodies
(d) ratio of emissive power to absorptive power is maximum for perfectly black body
(e) ratio of emissive power to absorptive power for all bodies is same and is equal to the emissive power of a perfectly black body.
Ans: e
63. All radiations in a black body are
(a) reflected
(b) refracted
(c) transmitted
(d) absorbed
(e) partly reflected and partly absorbed.
Ans: d
64. According to Kirchoff's law, the ratio of emissive power to absorptivity for all bodies is equal to the emissive power of a
(a) grey body
(b) brilliant white polished body
(c) red hot body
(d) black body
(e) none of the above.
Ans: d
65. The concept of overall coefficient of heat transfer is used in case of heat transfer by
(a) conduction
(b) convection
(c) radiation
(d) conduction and convection
(e) convection and radiation.
Ans: d
66. The unit of overall coefficient of heat transfer is
(a) kcal/m2
(b) kcal/hr °C
(c) kcal/m2 hr °C
(4) kacl/m hr °C
(e) kcal/m3 hr °C.
Ans: c
68. Joule sec is the unit of
(a) universal gas constant
(b) kinematic viscosity
(c) thermal conductivity
(d) Planck's constant
(e) none of the above.
Ans: d
69. The value of Portland number for air is about
(a) 0.1
(b) 0.3
(c) 0.7
(d) 1.7
(e) 10.5.
Ans: c
70. The value of the wavelength for maximum emissive power is given by
(a) Wien's law
(b) Planck's law
(c) Stefan's law
(d) Fourier's law
(e) Kirchhoff's law.
Ans: a
Read More Questions:
Heat Transfer - Mechanical MCQs Part1
Heat Transfer - Mechanical MCQs Part2
(a) one dimensional cases only
(b) two dimensional cases only
(c) three dimensional cases only
(d) regular surfaces having non-uniform temperature gradients
(e) irregular surfaces.
Ans: a
62. According of Kirchhoff law,
(a) radiant heat is proportional to fourth power of absolute temperature
(b) emissive power depends on temperature
(c) emissive power and absorptivity are constant for all bodies
(d) ratio of emissive power to absorptive power is maximum for perfectly black body
(e) ratio of emissive power to absorptive power for all bodies is same and is equal to the emissive power of a perfectly black body.
Ans: e
63. All radiations in a black body are
(a) reflected
(b) refracted
(c) transmitted
(d) absorbed
(e) partly reflected and partly absorbed.
Ans: d
64. According to Kirchoff's law, the ratio of emissive power to absorptivity for all bodies is equal to the emissive power of a
(a) grey body
(b) brilliant white polished body
(c) red hot body
(d) black body
(e) none of the above.
Ans: d
65. The concept of overall coefficient of heat transfer is used in case of heat transfer by
(a) conduction
(b) convection
(c) radiation
(d) conduction and convection
(e) convection and radiation.
Ans: d
66. The unit of overall coefficient of heat transfer is
(a) kcal/m2
(b) kcal/hr °C
(c) kcal/m2 hr °C
(4) kacl/m hr °C
(e) kcal/m3 hr °C.
Ans: c
68. Joule sec is the unit of
(a) universal gas constant
(b) kinematic viscosity
(c) thermal conductivity
(d) Planck's constant
(e) none of the above.
Ans: d
69. The value of Portland number for air is about
(a) 0.1
(b) 0.3
(c) 0.7
(d) 1.7
(e) 10.5.
Ans: c
70. The value of the wavelength for maximum emissive power is given by
(a) Wien's law
(b) Planck's law
(c) Stefan's law
(d) Fourier's law
(e) Kirchhoff's law.
Ans: a
Read More Questions:
Heat Transfer - Mechanical MCQs Part1
Heat Transfer - Mechanical MCQs Part2
No comments:
Post a Comment