Free Measurement and Instrumentation MCQs with Answers

• A. the same dimensions and the same number of turns
• B. the same dimension but different number of turns
• C. the same number of turns but different dimensions
• D. none of the above

Explanation: The two pressure coils of a single-phase dynamometer power-factor meter are made alike, with equal dimensions and equal turns, so their…

• A. one voltmeter and one ammeter
• B. one voltmeter, one ammeter and one wattmeter
• C. one voltmeter, one ammeter and one energy meter
• D. any of the above

Explanation: Power factor is calculated from cos φ = P/(VI), so voltage, current, and true power are required.

• A. moving coil instrument
• B. moving iron instrument
• C. dynamometer instrument
• D. none of the above

Explanation: A Weston synchronoscope uses the dynamometer principle, in which the interaction between fixed and moving coil magnetic fields produces…

• A. bus-bars
• B. incoming alternator
• C. a lamp
• D. none of the above

Explanation: In a Weston synchronoscope, the fixed-coil circuit is connected across the incoming alternator, while the other voltage circuit is…

• A. 0°
• B. 60°
• C. 90°
• D. 120°

Explanation: A dynamometer three-phase power-factor meter uses two moving-coil systems positioned with their planes 120° apart.

• A. parallel
• B. perpendicular
• C. inclined at 60°
• D. inclined at 120°

Explanation: The two fixed coils of a Weston frequency meter are arranged with perpendicular magnetic axes.

• A. exactly 0°
• B. approximately 0°
• C. exactly 90°
• D. approximately 90°

Explanation: One pressure-coil current is made nearly in phase with the supply voltage and the other nearly 90° out of phase by using a highly…

• A. one current circuit and two pressure circuits
• B. one current circuit and one pressure circuit
• C. two current circuits and one pres¬sure circuit
• D. none of the above

Explanation: A power-factor meter uses one current circuit and two pressure circuits to obtain the phase relationship between current and voltage.

• A. magnetic screening
• B. Wagner earthing device
• C. wave filters
• D. any of the above

Explanation: Magnetic screening surrounds the bridge or sensitive components with a magnetic shield, preventing external stray fields from inducing…

• A. Anderson bridge
• B. Maxwell's bridge
• C. Heaviside bridge
• D. Any of the above

Explanation: The Heaviside bridge is specifically used to measure mutual inductance.

• A. out of phase by 90°
• B. out of phase by 60°
• C. out of phase by 30°
• D. out of phase by 0°
• E. out of phase by 180°

Explanation: An AC coordinate potentiometer resolves voltage into in-phase and quadrature components, so its two potentiometer currents must differ in…

• A. electrostatic coupling
• B. electromagnetic coupling
• C. both A. and B.
• D. none of the above

Explanation: A Wagner earthing device removes errors caused by electrostatic coupling or stray capacitance between bridge components and earth.

• A. Maxwell's bridge
• B. Maxwell Wein bridge
• C. Hay's bridge
• D. Any of the above

Explanation: Hay's bridge is suitable for measuring high-Q coils, which generally have high inductance and comparatively small resistance.

• A. Maxwell bridge configuration for measurement of inductance and De Santas bridge for measurement of capacitance
• B. Maxwell Wein bridge for measurement of inductance and modified De Santy's bridge for measurement of capacitance
• C. Maxwell Wein bridge for measurement of inductance and Wein bridge for measurement of capacitance
• D. Any of the above

Explanation: A universal RLC bridge commonly combines the Maxwell-Wien arrangement for inductance with a modified De Sauty's arrangement for…

• A. unity
• B. 0.5
• C. 0.3
• D. zero

Explanation: In the two-wattmeter method, one reading becomes zero when the load angle is 60°, because one wattmeter measures a term proportional to…

• A. from a source which is not the same as the unknown voltage
• B. from a battery
• C. from the same source as the unknown voltage
• D. any of the above

Explanation: The AC potentiometer supply should be taken from the same source as the unknown voltage so that both have the same frequency and a stable…

• A. D.C. potentiometer
• B. Drysdale potentiometer
• C. A.C. co-ordinate potentiometer
• D. Crompton potentiometer

Explanation: A phase-shifting transformer is associated with the Drysdale AC potentiometer, where it provides the required adjustable phase…

• A. single-phase winding
• B. two-phase winding
• C. three-phase winding
• D. any of the above

Explanation: A phase-shifting transformer for an A.C. potentiometer generally uses two stator windings displaced by 90 electrical degrees, allowing the…

• A. directly by a D.C. potentiometer
• B. a D.C. potentiometer in conjunction with a volt ratio box
• C. a D.C. potentiometer in conjunction with a known resistance
• D. none of the above

Explanation: A D.C. potentiometer is normally suited to relatively small voltages; a volt ratio box scales a 200 V input down to a range suitable for…

• A. spring
• B. gravity
• C. coil
• D. eddy current

Explanation: A megger is a ratio-type instrument in which the pressure coil produces the controlling torque, while the current coil produces the…