471. What is the unit of thermal conductivity ?
Kcal/hr. m² °C
Kcal/hr.m.°C
Kcal/hr.m
Kcal/hr. °C
✅ The correct answer is option B.
Heat Transfer MCQs
472. In a forward feed multiple effect evaporator unit
Viscosity of liquid is highest in first effect
Transfer from effect to effect is done by pumps
No pump is required to withdraw the product from the last effect
None of these
✅ The correct answer is option D.
473. Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the
Surrounding temperature
Average temperature of the fin
Temperature of the fin end
Constant temperature equal to that of the base
✅ The correct answer is option D.
474. In a shell and tube heat exchanger, the tube side heat transfer co-efficient just at the entrance of the tube is
Infinity
Zero
Same as average heat transfer co-efficient for tube side
None of these
✅ The correct answer is option A.
475. In a multipass shell and tube heat exchanger, tube side return pressure loss is equal to __________ the velocity head.
Twice
Four times
Square root of
Square of
✅ The correct answer is option B.
476. Fqra cold viscous feed, backward feed gives __________ than forward feed.
A higher capacity
A lower capacity
Lower economy
None of these
✅ The correct answer is option A.
477. Heat waves
Can not pass through vacuum
Travel in straight line
Can be reflected by a mirror
Both B and C
✅ The correct answer is option D.
478. In a shell and tube type heat exchanger, the floating tube bundle heat arrangement is used
In low range of temperature differences
In high range of temperature differences
Because of its low cost
To prevent corrosion of the tube bundles
✅ The correct answer is option B.
479. Increasing the liquor level in the evaporator results in the
Decreased capacity
Increase in liquor film co-efficient
Decreased effect of hydrostatic head
Increased true temperature drop
✅ The correct answer is option A.
480. Terminal point temperature differences between fluids in case of a heat exchanger is termed as
Approach
Log mean temperature difference
Arithmetic mean temperature difference
Geometric mean temperature difference
✅ The correct answer is option A.