Page |1
MEEN 464 Final Exam Questions and
Correct Answers/ Latest Update / Already
Graded
A thermistor is a temperature sensor that contains metallic wire that
changes its electrical resistance when the temperature changes.
Ans: True
A Bi-metallic Dial Thermometer is a temperature sensor that contains
the liquid that changes its volume when the temperature changes.
Ans: FALSE --> contains metal strips, not liquid
Due to harsh conditions, a sheath may be used to protect a
thermocouple. The time constant of the thermocouple will be smaller
due to the sheath
Ans: FALSE --> TC's will be HIGHER
Which thermocouple will have the shortest time constant?
Ans: 30-gage T-type thermocouple with an exposed junction
***Not sheathed, more diameter increases time constant, K < T
All rights reserved © 2025/ 2026 |
, Page |2
Time Constant
Ans: T = (t1 +t2) / 2
find t it takes for T = t1
subtract --> t1 -ti = t(1/2)
TIME CONSTANT = t(1/2) / ln(2)
Heat Transfer through a rod (lab 2)
Ans: Q = -kA(dt/dx)
The two collinear rods are then subjected to long exposure in salt
water, and thus pitting corrosion has occurred at the interface. If the
rods are used for further testing, the thermal contact resistance should
be expected to increase. (lab 3)
Ans: surface pitting involves defects on the surface, thus
substantially increasing the roughness. The thermal contact
resistance should be expected to increase.
The thermal contact resistance should be expected to increase when
the rods are pressed against each other (lab 3)
All rights reserved © 2025/ 2026 |
, Page |3
Ans: FALSE (gap is closing --> increasing pressure means
decreasing resistance)
Dimensionless Temperature (Lab 4)
Ans: (T - T_inf) / (T_base - T_inf)
Biot number equation/rule (Lab 5)
Ans: (h *(V/A_s)) / k
Bi MUST BE < 0.1 for Lumped Capacitance
Counter-flow concentric tube heat exchanger problem (Lab 7)
Ans: mc(delta_T) = m1c1(delta_T1) --> solve for specific
inlet/outlet temp
Thi - Tho = delta_T
Tco - Tci = delta_T1
--> Total Rate of HT = (mh)(mc)(delta_Th)
All rights reserved © 2025/ 2026 |
MEEN 464 Final Exam Questions and
Correct Answers/ Latest Update / Already
Graded
A thermistor is a temperature sensor that contains metallic wire that
changes its electrical resistance when the temperature changes.
Ans: True
A Bi-metallic Dial Thermometer is a temperature sensor that contains
the liquid that changes its volume when the temperature changes.
Ans: FALSE --> contains metal strips, not liquid
Due to harsh conditions, a sheath may be used to protect a
thermocouple. The time constant of the thermocouple will be smaller
due to the sheath
Ans: FALSE --> TC's will be HIGHER
Which thermocouple will have the shortest time constant?
Ans: 30-gage T-type thermocouple with an exposed junction
***Not sheathed, more diameter increases time constant, K < T
All rights reserved © 2025/ 2026 |
, Page |2
Time Constant
Ans: T = (t1 +t2) / 2
find t it takes for T = t1
subtract --> t1 -ti = t(1/2)
TIME CONSTANT = t(1/2) / ln(2)
Heat Transfer through a rod (lab 2)
Ans: Q = -kA(dt/dx)
The two collinear rods are then subjected to long exposure in salt
water, and thus pitting corrosion has occurred at the interface. If the
rods are used for further testing, the thermal contact resistance should
be expected to increase. (lab 3)
Ans: surface pitting involves defects on the surface, thus
substantially increasing the roughness. The thermal contact
resistance should be expected to increase.
The thermal contact resistance should be expected to increase when
the rods are pressed against each other (lab 3)
All rights reserved © 2025/ 2026 |
, Page |3
Ans: FALSE (gap is closing --> increasing pressure means
decreasing resistance)
Dimensionless Temperature (Lab 4)
Ans: (T - T_inf) / (T_base - T_inf)
Biot number equation/rule (Lab 5)
Ans: (h *(V/A_s)) / k
Bi MUST BE < 0.1 for Lumped Capacitance
Counter-flow concentric tube heat exchanger problem (Lab 7)
Ans: mc(delta_T) = m1c1(delta_T1) --> solve for specific
inlet/outlet temp
Thi - Tho = delta_T
Tco - Tci = delta_T1
--> Total Rate of HT = (mh)(mc)(delta_Th)
All rights reserved © 2025/ 2026 |
