Manometer MCQ – Fluid Mechanics

1. Pressure of a fluid is measured by a

  1. barometer
  2. manometer
  3. lactometer
  4. thermometer
  5. submerged height
Answer
Answer. b

2. The liquid used in manometers should have

  1. low density
  2. high density
  3. low surface tension
  4. high surface tension
Answer
Answer. b

3. Manometers are used to measure

  1. pressure in water channels, pipes, etc.
  2. difference in pressure at two points
  3. atmospheric pressure
  4. very low pressure
Answer
Answer. a

4. Micro-manometer is used to

  1. determine low pressure difference
  2. determine higher pressure difference
  3. pressure measurement for gases only
  4. measure pressure in congested areas
Answer
Answer. a

5. The difference in pressure head, measured a mercury water differential manometer for 20 cm difference of mercury will be

  1. 2.52 m
  2. 2.72 m
  3. 0.2 m
  4. 2.0 m
Answer
Answer. a

6. Mercury is generally used in manometers for measuring

  1. low pressure accurately
  2. large pressure only
  3. all pressures except the small ones
  4. very low pressure
Answer
Answer. a

7. The reading on a differential manometer containing mercury (specific gravity= 13.6) is 25 cm. If mercury is replaced with water, the reading on differential manometer would be

  1. 3.15 m
  2. 3.4 m
  3. 34 m
  4. 31.5 cm
Answer
Answer. b

8. A differential manometer is used to measure

  1. pressure in Venturimeter
  2. difference of pressure between two points in a pipe
  3. atmospheric pressure
  4. pressure in pipes
Answer
Answer. b

9. Multi U-tube manometers with different fluids are used to measure

  1. very low pressure
  2. low pressure
  3. medium pressure
  4. high pressure
Answer
Answer. b

10. If a mercury-oil differential manometer shows a 20 cm difference of mercury level, the difference in the pressure head is (consider the specific gravity of oil = 0.8)

  1. 2.0 m of oil
  2. 2.5 m of oil
  3. 3.2 m of oil
  4. 4.2 m of oil
Answer
Answer. c

11. Air flows through a duct, and the Pitot-static tube measuring the velocity is attached to a differential manometer containing water. If the deflection of the manometer is 100mm, assuming the density 0f air is constant and equals to 1.22 kg/m3, and that the coefficient of the tube is 0.98. The air velocity will be

  1. 4.07 m/s
  2. 0.393 m/s
  3. 39.3 m/s
  4. 3.93 m/s
Answer
Answer. c

12. The reading of differential manometer of a venturimeter, placed at 45° to the horizontal is 11 cm. If the venturimeter is turned to horizontal position, the manometer reading will be

  1. 0
  2. 11 cm
  3. $\frac{1}{\sqrt{2}}$cm
  4. $11\sqrt{2}$cm
Answer
Answer. b

13. A horizontal pipe line conveys a constant rate of flow which is measured by venturimeter installed on it. When the pipe is inclined upwards in the direction of flow, the reading of level difference on a differential U-tube manometer

  1. will increase
  2. will remain same
  3. will decrease
  4. may fluctuate with time
Answer
Answer. b

14. A pipe contains an oil of specific gravity 0.9, A differential manometer connected at the two points A and B shows a difference in mercury levels as 15 cm. The difference of pressure at the two points A and B will be (Note: consider the density of mercury as 1360 kg/m3)

  1. 15981 N/m2
  2. 18688 N/m2
  3. 6528 N/m2
  4. 288 N/m2
Answer
Answer. b