Question  set 164

Thermometric Well

1.     The convective coefficient in boilers and condenser is
a) Low
b) High
c) Moderate
d) Depends on time and temperature
Answer: b
Explanation: For low heat transfer rate it is high.

2.     In thermometer, heat is dissipated from which end?
a) Back side
b) Front side
c) Middle
d) No heat is dissipated
Answer: a
Explanation: In thermometric well heat dissipation is from the end.

3.     The thermometric well is treated as a fin of
a) It is not treated as a fin
b) Infinite length
c) Finite length
d) It depends on the amount of heat dissipation
Answer: c
Explanation: Generally for maximum heat dissipation it is treated as a fin of finite length.

4.     Thermometric well apparatus doesn’t consist of
a) Thermometer
b) Pipe line
c) Oil
d) Ammeter
Answer: d
Explanation: It doesn’t consist of an ammeter.

5.     For what purpose we use thermometric well?
a) To measure current
b) To measure resistance
c) To measure temperature of gas
d) To stop heat dissipation
Answer: c
Explanation: We use this apparatus for the measurement of a temperature of gas flowing through pipeline.

6.     In thermometric well, the error can be minimized by
(i) The value of parameter ml slows down by some quantity.
(ii) Lagging of the tube so that conduction of heat along its length is arrested.
a) True
b) False
Answer: b
Explanation: Here, we increase the value of parameter ml.

7.     Suppose there are two reservoirs A and B. Let T_A and T_B be the temperatures of respective reservoirs. At any instant say T_A = T_B. In this case, maximum temperature occurs at
a) Middle
b) Left
c) Right
d) All over the rod
Answer: a
Explanation: Here temperatures are same so x = ½ i.e. middle of the rod.

8.     The relevant boundary conditions in case of heat transfer from a bar connected to two heat sources at different temperatures are
a) α = α ₁ at x = 0 and α = α ₂ at x = infinity
b) α = α ₁ at x = 1 and α = α ₂ at x = 2L
c) α = α ₁ at x = infinity and α = α ₂ at x = 1
d) α = α ₁ at x = 0 and α = α ₂ at x = L
Answer: d
Explanation: It should be at x = o and x = L.

9.     “The tube that is used in a thermometric well is considered as a hollow fin and the temperature distribution is obtained by using the relation applicable to infinitely long fin”.
a) True
b) False
Answer: b
Explanation: The relation applicable to fin with insulated tip is used here.

10. “The diameter of well does not have any effect on temperature measurement by the thermometer”.
a) True
b) False
Answer: a
Explanation: Here, there is no relation between well diameter and temperature.