E-PolyLearning

56. With respect to the equation k = k0 (1 +β t) which is true if we put β = 0?
a. Slope of temperature curve is constant
b. Slope of temperature curve does not change
c. Slope of temperature curve increases
d. Slope of temperature curve is decreases
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Answer: (a).Slope of temperature curve is constant

57. If β is greater than zero, then choose the correct statement with respect to given relation
k = k0 (1 +β t)
a. k doesn’t depends on temperature
b. k depends on temperature
c. k is directly proportional to t
d. Data is insufficient
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Answer: (c).k is directly proportional to t

58. The unit of thermal conductivity doesn’t contain which parameter?
a. Watt
b. Pascal
c. Meter
d. Kelvin
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Answer: (b).Pascal

59. The temperatures on the two sides of a plane wall are t1 and t2 and thermal conductivity of the wall material is prescribed by the relation
K = k0 e^(-x/δ)

Where, k0 is constant and δ is the wall thickness. Find the relation for temperature distribution in the wall?
a. t 1 – t x / t 1 – t 2 = x
b. t 1 – t x / t 1 – t 2 = δ
c. t 1 – t x / t 1 – t 2 = δ/x
d. t 1 – t x / t 1 – t 2 = x/δ
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Answer: (d).t 1 – t x / t 1 – t 2 = x/δ

60. “If β is less than zero, then with respect to the relation k = k0 (1 + β t), conductivity depends on surface area”. True or false
a. True
b. False
c. May be
d. Can't say
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Answer: (b).False