Section 1 - Measurements and Instrumentation

Question 1

A PMMC (Permanent Magnet Moving Coil) instrument responds to:

A. RMS value of AC current only

B. Average value of the current

C. Peak value of the current

D. Instantaneous value of the current

Question 2

A PMMC instrument cannot be used directly to measure AC because:

A. It is too sensitive

B. The average value of a pure sinusoidal AC current is zero

C. It responds to peak values

D. It has a non-linear scale

Question 3

The deflection of a moving iron instrument is proportional to:

A. The current

B. The square of the current

C. The cube of the current

D. The square root of the current

Question 4

A moving iron instrument is suitable for measuring:

A. DC only

B. AC only

C. Both DC and AC (RMS value)

D. Very high frequency signals

Question 5

To extend the range of an ammeter, a shunt is connected:

A. In series with the meter

B. In parallel with the meter

C. Directly to the source

D. Between phase and neutral

Question 6

To extend the range of a voltmeter, a multiplier resistance is connected:

A. In parallel with the meter

B. In series with the meter

C. In series with the load

D. In parallel with the load

Question 7

The sensitivity of a voltmeter is expressed in:

A. Volts per ampere

B. Ohms per volt

C. Amperes per volt

D. Volts per ohm

Question 8

A wattmeter measures:

A. Only real (active) power

B. Only reactive power

C. Only apparent power

D. Only power factor

Question 9

The two-wattmeter method is used to measure:

A. Single-phase power

B. Three-phase power in a three-phase, three-wire system

C. DC power only

D. Only reactive power

Question 10

An energy meter measures:

A. Instantaneous power

B. Electrical energy consumed over time

C. Peak voltage

D. Power factor

Question 11

A Wheatstone bridge is used for the accurate measurement of:

A. Low resistances (below 1 ohm)

B. Medium resistances

C. Very high resistances (above 100 M ohm)

D. Capacitance

Question 12

A Kelvin double bridge is used for the accurate measurement of:

A. High resistances

B. Low resistances (below 1 ohm)

C. Inductance

D. Frequency

Question 13

A Maxwell bridge is used for the measurement of:

A. Low-Q inductance in terms of a known capacitance

B. High-Q inductance only

C. Capacitance in terms of resistance

D. Frequency

Question 14

A Schering bridge is commonly used for the measurement of:

A. Inductance

B. Capacitance and dissipation factor of dielectrics

C. Frequency

D. Low resistance

Question 15

A Wien bridge is used for the measurement of:

A. Resistance only

B. Inductance only

C. Frequency (and can measure capacitance)

D. Voltage only

Question 16

A thermistor is a transducer whose:

A. Resistance is independent of temperature

B. Resistance changes significantly with temperature

C. Capacitance changes with pressure

D. Inductance changes with temperature

Question 17

A strain gauge is a transducer used to measure:

A. Temperature

B. Mechanical strain (deformation)

C. Light intensity

D. Magnetic field

Question 18

An LVDT (Linear Variable Differential Transformer) is used to measure:

A. Temperature

B. Linear displacement

C. AC frequency

D. Magnetic flux

Question 19

A piezoelectric transducer generates an electrical output in response to:

A. Temperature change

B. Mechanical stress or pressure

C. Magnetic field

D. Light

Question 20

A thermocouple works on the principle of:

A. Photoelectric effect

B. Seebeck effect (thermoelectric EMF at a junction of dissimilar metals)

C. Hall effect

D. Piezoelectric effect

Question 21

The horizontal deflection plates of a CRO are typically connected to:

A. The input signal directly

B. The internal time-base (sweep) generator

C. The vertical amplifier

D. A DC power supply

Question 22

Lissajous patterns on a CRO are used to determine:

A. Only the amplitude of a signal

B. The frequency and phase relationship between two signals

C. The DC offset only

D. The rise time of a pulse

Question 23

The main advantage of a digital multimeter (DMM) over an analog multimeter is:

A. Lower cost only

B. Higher input impedance, better accuracy, and direct numeric readout

C. Faster mechanical movement

D. Ability to measure only DC

Question 24

The resolution of an n-bit ADC (analog-to-digital converter) with full-scale range V_FS is:

A. V_FS / n

B. V_FS / 2^n

C. V_FS * n

D. V_FS * 2^n

Question 25

In a Q-meter, the quality factor Q of a coil is measured by:

A. Comparing the voltage across the capacitor to the applied voltage at resonance

B. Measuring the DC resistance only

C. Measuring the leakage inductance only

D. Comparing input current with output current

Questions

Section 1 - Measurements and Instrumentation - Set 1