# Instrumentation Transducers Questions and Answers – Servo Operated Electro Magnetic Flowmeter

This set of Instrumentation Transducers MCQs focuses on “Servo Operated Electro Magnetic Flowmeter”.

1. Which of the following are not suitable with electromagnetic flow meter?
a) Steady flowing liquid
b) Slurries
c) Liquid containing particulate matter
d) None of the mentioned

Explanation: Electromagnetic flow meter can be used with all type of liquid.

2. Output signal of electromagnetic flow meter inversely proportional to _________________
a) Magnetic flux density
b) Diameter of tube
c) Velocity of flow
d) None of the mentioned

Explanation: E= BDV, where B is the magnetic flux density, D is the diameter of the tube and V is the velocity of flow.

3. Frequency of AC electromagnets are independent of magnetic flux density.
a) True
b) False

Explanation: For 50 Hz AC electromagnetic flow meter, magnetic flux density may fluctuate.

4. Feedback system in electromagnetic flow meter is applied to ______________
a) Overcome fluctuation of B
b) Reduce measuring time
c) Reduce excitation supply
d) None of the mentioned

Explanation: Feedback system in electromagnetic flow meter is used to overcome fluctuation of B.

5. Feedback system draws current from the main circuit.
a) True
b) False

Explanation: Feedback system connected will not draw any current from the main circuit.

6. Servo operated electromagnetic flow meter is _________________
a) Zero order system
b) First order system
c) Second order system
d) Third order system

Explanation: Presence of servomotor in a forward path made a second order system.

7. Electromagnetic flow meter is based on ________________
a) Coulomb’s law
b) Law of electromagnetic induction
c) Kirchhoff law
d) Newton’s law

Explanation: Electromagnetic flow meters are based on law of electromagnetic induction.

8. Which for the following represents condition for maximum emf?
a) Electrodes parallel to pipe length
b) Electrodes parallel to flow
c) Electrodes across flow
d) None of the mentioned

Explanation: For maximum emf to be produced electrodes are placed across flow.

9. Which of the following device is used for measuring emf between electrodes?
a) Low impedance type voltmeter
b) High impedance voltmeter
c) No specification for voltmeter
d) None of the mentioned

Explanation: If low impedance is used, there will be a drop due to the internal resistance of liquid.

10. Which of the following factors electromagnetic flow meters are sensitive to?
a) Temperature of fluid
b) Viscosity of fluid
c) Density of fluid
d) None of the mentioned

Explanation: Electromagnetic flow meters are insensitive to temperature, viscosity and density of a fluid.

Sanfoundry Global Education & Learning Series – Instrumentation Transducers.

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