Instrumentation: Part-2 Objective Questions

Solved Objective Questions from Measurements & Instrumentation:

[1] An oscilloscope cannot be used to indicate

A.  Frequency

B.  Peak signal voltage

C.  Energy

D.  Wave shape

Ans: C

[2] In two watt meter method of power measurement, if one of the watt meter shows zero reading, then it can be concluded that

A. Power factor is unity

B. Power factor is zero

C. Power factor is 0.5 lagging

D. Power factor is 0.5 leading

Ans: C

[3] voltmeters should generally have

A.  High internal resistance

B.  Low internal resistance

C.  The ability to withstand large currents

D.  The greatest possible sensitivity

Ans:A

[4] To measure the applied power supply voltage to the electrical circuit, the voltmeter should be placed

A.  In series with the circuit that works from the supply

B.  Between the positive pole of the supply and the circuit working from the supply

C.  Between the negative pole of the supply and the circuit working from the supply

D.  In parallel with the circuit that works from the supply

Ans:D

[5] Which will not normally cause a large error in an ohmmeter reading?

A.  A slight change in switchable internal resistance

B.  A small voltage between points under test

C.  A small change in the resistance to be measured

D.  A slight error in the range switch position

Ans:C

[6] Which  is not function of the fuse?

A.  To ensure there is enough current available for and appliance to work right

B.  To make sure the current drawn by an appliance can not exceed a certain limit

C.  To limit the amount of power that a device can draw from the electrical circuit

D.  To make it impossible to use appliances that are too large for a given circuit

Ans: A

[7] The utility meter’s motor speed depends directly on

A.  The number of watt hours being used at the time

B.  The number of ampere hours being used at the time

C.  The number of watts being used at the time

D.  The number of kilowatt hours being used at the time

Ans: C

[8] A typical frequency counter

A.  Works by indirectly measuring voltage

B.  Is accurate to six digits or more

C.  Works by indirectly measuring current

D.  Has an analog readout

Ans: B

[9] A VU meter is never used to get a general indication of

A.  Sound intensity

B.  Visible light intensity

C.  Power in an audio amplifier

D.  Decibels

Ans:D

[10] An analog voltmeter has a sensitivity of 10k/volt. The galvanometer used in constructing the instrument will produce a full scale deflection when the current passed through it is

(a) 10 mA

(b) 20 mA

(c) 50 mA

(d) 100 μA

Ans: D

[11] Two sinusoidal signals of the same frequency are displayed on a dual-trace oscilloscope. One complete cycle of each signal covers 6 cm of the horizontal scale and the starting point of the horizontal scale and the starting point of the two signals are separated by 0.5 cm. The phase difference between the two signals in degrees is

(a) 30

(b) 45

(c) 60

(d) 90

Ans: A

[12] Transient signals can be observed using

(a) Storage oscilloscope

(b) Sampling oscilloscope

(c) Wave analyzer

(d) Spectrum analyzer

Ans: A

[13] The trace on an oscilloscope continually moves to the right of the screen when

(a) The sweep is triggered.

(b) The sweep period is larger than the signal period.

(c) The sweep period is smaller than the signal period.

(d) There is no weep.

Ans: C

[14] In a dual trace oscilloscope, the display appears segmented when

(a) Low frequency signals are observed in Alternate mode

(b) Low frequency signals are observed in Chop mode

(c) High frequency signals are observed in Alternate mode

(d) High frequency signals are observed in Chop mode

Ans: D

[15] The meter movement in an illumination meter directly measures

A.  Current

B.  Power

C.  Voltage

D.  Energy

Ans:A