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- Question
The operating speed of a ball mill should be __________ the critical speed.
Options- A. less than
- B. much more than
- C. at least equal to
- D. slightly more than
- Correct Answer
- less than
- 1. In case of hydraulically smooth pipe, the resistance to flow depends only on the Reynolds number, whereas for a hydraulically rough pipe, the resistance to flow is governed by the relative roughness. Two pipes are said to have the same hydraulic roughness, when they have equal values of
Options- A. relative roughness.
- B. absolute roughness.
- C. friction co-efficient for flows at equal Reynold number.
- D. all (a), (b) & (c). Discuss
- 2. The terminal velocity of a small sphere settling in a viscous fluid varies as the
Options- A. first power of its dimeter.
- B. inverse of the fluid viscosity.
- C. inverse square of the diameter.
- D. square of the difference in specific weights of solid & fluid. Discuss
- 3. The main differentiation factor between tube mill and ball mill is the
Options- A. length to diameter ratio.
- B. size of the grinding media.
- C. final product size.
- D. operating speed. Discuss
- 4. The net positive suction head (NPSH) of a centrifugal pump is defined as the sum of the velocity head and the pressure head at the
Options- A. discharge.
- B. suction.
- C. suction minus vapor pressure of the liquid at suction temperature.
- D. discharge minus vapor pressure of the liquid at the discharge temperature. Discuss
- 5. Net efficiency of ordinary light water cooled nuclear reactor is about __________ percent.
Options- A. 32
- B. 52
- C. 72
- D. 88 Discuss
- 6. With increase in density, the viscosity of petroleum products
Options- A. increases
- B. decreases
- C. remains same
- D. either (a) or (b) Discuss
- 7. Which of the following is the most adverse factor challenging the choice of mercury electrolytic cell process for the production of caustic soda?
Options- A. High cost of mercury.
- B. High specific gravity of mercury.
- C. Non-availability of high purity mercury.
- D. Pollution of water stream by mercury. Discuss
- 8. Working principle of disappearing filament type optical pyrometer is based on the
Options- A. Wien's law
- B. Seebeck effect
- C. Kirchoff's law
- D. Peltier effect Discuss
- 9. Configuration of Bourdon spring tube is never made of __________ shape.
Options- A. circular
- B. semi-circular
- C. helical
- D. spiral Discuss
- 10. A negative gain margin expressed in decibels means a/an __________ system.
Options- A. stable
- B. unstable
- C. critically damped
- D. none of these Discuss
More questions
Correct Answer: friction co-efficient for flows at equal Reynold number.
Correct Answer: inverse of the fluid viscosity.
Correct Answer: length to diameter ratio.
Correct Answer: suction minus vapor pressure of the liquid at suction temperature.
Correct Answer: 32
Correct Answer: increases
Correct Answer: Pollution of water stream by mercury.
Correct Answer: Wien's law
Correct Answer: circular
Correct Answer: unstable
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