Electrical Measuring Devices 7

Objectives for Electrician and Wireman: Electrical Measuring Devices 7

Part 7: Objective questions and answers of Electrical Measuring Devices

Q1. The PMMC type meter is working on the principle as same as:

a) Dc generator

b) Transformer

c) Moving iron meter

d) Dc motor

Q2. Which one is a disadvantage of a PMCC instrument?

a) Consumes less power

b) Has efficient damping

c) Can be used in dc only

d) Has high torque/weight ratio

Q3. Which type of instrument belongs to the integrating instrument type?

a) Energy meter

b) Voltmeter

c) Ammeter

d) Electro cardio graph (ECG)

Q4. The error caused by the effect of vibrations is:

a) Device errors

b) Switching errors

c) Influence errors

d) Human errors

Q5. Fine scale instruments are used for precision with accuracy from:

a) 0.1 to 0.15

b) 0.1 to 0.2

c) 0.1 to 0.3

d) 0.1 to 0.4

Q6. Controlling force always acts:

a) Opposite to the deflection force

b) Same direction of the deflection force

c) Not to allow to move

d) To keep the pointer in the same place

Q7. The material used for spring control in instrument is:

a) Manganin

b) Eureka

c) Phosphor bronze

d) Silver

Q8. The unit of sensitivity of the instrument is:

a) Ohms/volt

b) Volt/ohm

c) Volt-amp

d) Ampere/sec

Q9. A good example of an absolute instrument is:

a) Volt meter

b) Ammeter

c) Tangent galvanometer

d) Wattmeter

Q10. The deflecting force of repulsion type M.I. Instruments is directly proportional to:

a) The current

b) The voltage

c) The square of the current

d) The magnetic field

Q11. Which one is application of current transformer (CT)?

a) Auto transformer

b) Tong tester

c) Earth leakage circuit breaker (ELCB)

d) Variac

Q12. Which is the main precaution to be taken before any measurement by using tong tester?

a) Set the tester in correct range

b) Make looping the conductor more than once through the core

c) Make sure the induction is at zero on the scale

d) Read the indicator position on the scale

Q13. In 3 elements 3 phase energy meter, how many number of aluminum discs are mounted?

a) 1

b) 2

c) 3

d) 4

Q14. Which one of the following blocks does not consist of D.S.O.?

a) Data acquisition

b) Data display

c) Storage

d) Filter

Q15. What is the peak voltage of 250 v, r.m.s. Main a.c. Voltage in C.R.0.?

a) 250 volts

b) 320 volts

c) 353.5 volts

d) 368.3 volts

Q16. Which control switch is used to control the sharpness of the trace in CRO?

a) Intensity control switch

b) Time base switch

c) Cal – switch

d) Alternator switch

Q17. Which one of the following is not an advantage of a PMMC instrument?

a) Consumes less power

b) Is very delicate

c) Has efficient damping

d) Has no less due to hysteresis

Q18. The examples for integrating instruments are:

a) Voltmeter

b) Ammeter

c) Ampere hour meter

d) Wattmeter

Q19. Which one of the following meter belongs to the integrating type instrument?

a) Voltmeter

b) Energy meter

c) Ammeter

d) Watt meter

Q20. The error of false adjustment of the instruments is:

a) Influence errors

b) Switching errors

c) Device errors

d) Human errors

Part 7: Objective questions and answers of Electrical Measuring Devices