Wattmeter Theory And Measurement of Power - 1 - MCQs

Wattmeter Theory And Measurement of Power - 1 - MCQs

Q1. In case of dc supply and in case of ac supply, the torque produced is

A. Directly proportional to power, inversely power to power

B. Directly proportional to power, directly proportional to power

C. Inversely proportional to power, inversely proportional to power

D. Inversely proportional to power, directly proportional to power

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Q2. The scale of dynamometer wattmeter is

A. Approximately uniform
B. Cramped at the middle
C. Cramped at the end points
D. Crowded in the first half

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Q3. In standard wattmeter’s, the error caused by the voltage coil is overcome by

A. Connecting a high inductive resistance in series to the voltage coil

B. Connecting a high inductive resistance in parallel to the voltage coil

C. Connecting a compensating winding in series to the voltage coil

D. Connecting a compensating winding in parallel to the voltage coil

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Q4. In a dynamometer type wattmeter, the pressure coil connected across the load terminal is

A. Highly inductive
B. Highly capacitive
C. Highly resistive
D. Non inductive

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Q5. The dynamometer wattmeter’s are

A. More accurate on dc supply
B. More accurate on ac supply
C. Equally accurate on both ac and dc supply
D. None of these

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Q6. Due to the inductance in the pressure coil of dynamometer type wattmeter, the reading will be

A. High for both leading and lagging power factors
B. Low for both leading and lagging power factors
C. High for lagging power factor and low for leading power factor
D. Low for lagging power factor and high for leading power factor

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Q7. What will happen if the current coil and potential coil of dynamometer type wattmeter is interchanged?

A. Potential coil will get damaged
B. Current coil will get damaged
C. Both current coil and potential coil will get damaged
D. Neither potential coil nor current coil will get damaged

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Q8. In some wattmeter’s, a small capacitor is connected in parallel with the series resistor for

A. Reducing error due to inductance of the series resistor
B. Obtaining non inductive voltage coil current
C. Making resultant reactance capacitive
D. All of these

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Q9. In wattmeter’s, errors due to stray fields can be removed by

A. Proper instrument construction
B. Using brake magnet
C. Using shading ring
D. Using two separate ac magnets

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