MCQs
Total Questions : 75
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Question 1. Consider the following statements pertaining to heat transfer through fins
(i) They must be arranged at right angles to the direction of flow of working fluid
(ii) The temperature along the fin is variable and accordingly heat transfer rate varies along the fin elements
(iii) Fins are equally effective irrespective whether they are on the hot side or cold side of the fluid
(iv) Fins are made of materials that have thermal conductivity higher than that of wall
Identify the correct statements
(i) They must be arranged at right angles to the direction of flow of working fluid
(ii) The temperature along the fin is variable and accordingly heat transfer rate varies along the fin elements
(iii) Fins are equally effective irrespective whether they are on the hot side or cold side of the fluid
(iv) Fins are made of materials that have thermal conductivity higher than that of wall
Identify the correct statements
Answer: Option D. -> 1 and 2
Answer: (d).1 and 2
Answer: (d).1 and 2
Question 2. The handle of a saucepan, 30 cm long and 2 cm in diameter, is subjected to 100 degree Celsius temperature during a certain cooking operation. The average unit surface conductance over the handle surface is 7.35 W/m² degree in the kitchen air at 24 degree Celsius. The cook is likely to grasp the last 10 cm of the handle and hence the temperature in this region should not exceed 38 degree Celsius. What should be the thermal conductivity of the handle material to accomplish it? The handle may be treated as a fin insulated at the tip
Answer: Option B. -> 17.36 W/m degree
Answer: (b).17.36 W/m degree
Answer: (b).17.36 W/m degree
Answer: Option C. -> 2 and 4
Answer: (c).2 and 4
Answer: (c).2 and 4
Answer: Option C. -> Fin effectiveness = A FIN/A B (Efficiency of fin)
Answer: (c).Fin effectiveness = A FIN/A B (Efficiency of fin)
Answer: (c).Fin effectiveness = A FIN/A B (Efficiency of fin)
Answer: Option D. -> Increase in heat transfer
Answer: (d).Increase in heat transfer
Answer: (d).Increase in heat transfer
Answer: Option B. -> Fin effectiveness is improved if fin is made from a material of low conductivity
Answer: (b).Fin effectiveness is improved if fin is made from a material of low conductivity
Answer: (b).Fin effectiveness is improved if fin is made from a material of low conductivity
Answer: Option C. -> Finite length
Answer: (c).Finite length
Answer: (c).Finite length
Answer: Option B. -> High
Answer: (b).High
Answer: (b).High
Answer: Option D. -> Ammeter
Answer: (d).Ammeter
Answer: (d).Ammeter
Answer: Option A. -> Back side
Answer: (a).Back side
Answer: (a).Back side