Electrical Measuring Devices 2

Objectives for Electrician and Wireman: Electrical Measuring Devices 2

Subject: Electrical Measuring Devices 2

Part 2: objective questions and answers of Electrical Measuring Devices

Q1. Which force is required to move the pointer from zero position in an indicating instrument?

a) Controlling force

b) Deflecting force

c) Air friction damping

d) Eddy current damping

Q2. Which error is caused by the incorrect position of instrument reading?

a) Device error

b) Human error

c) Influence error

d) Switching error

Q3. What is the purpose of the 3rd terminal provided in an advanced megohm meter?

a) Get higher ohmic values

b) Pass the excess voltage to ground

c) Pass the excess current to ground

d) Get accurate readings without oscillation

Q4. What is the effect on ct if its secondary is kept open?

a) Ct primary burns out

b) Volt ampere capacity reduces

c) Volt ampere capacity increases

d) Ct secondary winding burns out

Q5. Which material is used to make control spring in measuring instruments?

a) Steel

b) Silver

c) Tinned copper

d) Phosphor bronze

Q6. Which is the position to use the instrument provided with spring control?

a) Any position

b) Vertical position only

c) Inclined position only

d) Horizontal position only

Q7. How the creeping error is controlled in energy meter?

a) By reducing rated voltage

b) By increasing the inductive load

c) Deflection of force is directly proportional to the square of the current

d) Deflection force is inversely proportional to the square of the current

Q8. Which source of measuring error is caused by the effect of magnetic fields?

a) Device error

b) Human error

c) Influence error

d) Switching error

Q9. Which type of energy meter works with neutral connection?

a) Three phase two element

b) Three phase three element

c) Single phase single element

d) Three phase two element with ct & pt

Q10. Why two straight holes are provided in the aluminum disc in energy meter?

a) To reduce the disc weight

b) For power factor correction

c) To prevent the flux leakage

d) To arrest the creeping error

Q11. What is the function of soft iron core in a moving coil instrument?

a) Strengthens the deflection force

b) Controls the needle's movement

c) Provides meter with maximum sensitivity

d) Provide uniform distribution of magnetic flux in air gap

Q12. Which meter is used to measure revolution per minute of a motor?

a) Tachometer

b) Energy meter

c) Ampere hour meter

d) Centre zero ammeter

Q13. Which is an absolute instrument?

a) Ammeter

b) Volt meter

c) Energy meter

d) Tangent galvanometer

Q14. What is the function of integrating instrument?

a) Displays the quantity

b) Indicates the quantity

c) Registers the quantity

d) Measures the quantity

Q15. Which quantity is measured by an electro dynamo type instrument?

a) Power

b) Current

c) Voltage

d) Resistance

a) Keep low input impedance

b) Keep high input impedance

d) Provide correct damping system

Q17. In a moving coil instrument, the damping torque is developed by:

a) Air-friction

b) Eddy-current

c) Gravity-friction

d) Fluid-friction

Q18. M.c. Type instruments are used on:

a) A.C.

b) D.C.

c) A.C. Or D.C.

d) None of these

Q19. The force which produces movement of the pointer of an instrument is called:

a) Deflecting force

b) Controlling force

c) Damping force

d) Distracting force

Q20. When using any instrument for measurement or testing purpose, first attention should be given to the:

a) Theoretical knowledge

b) Personal safety

c) Surroundings

d) Dress

Part 2: objective questions and answers of electrical measuring devices