Potentiometer method of dc voltage measurement is more accurate than direct meas

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Question
Potentiometer method of dc voltage measurement is more accurate than direct measurement using a voltmeter because
Options
A. it loads the circuit to maximum extent
B. it loads the circuit moderately
C. it does not load the circuit at all
D. it uses centre zero galvanometer instead of Voltmeters

Correct Answer

it does not load the circuit at all

Explanation

Since the circuit is not loaded, the accurate value of dc voltage is measured.

Measurements and Instrumentation problems

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1. Which of the following voltmeters would you use for measuring voltage across 20 k? resistance?
Options
A. Voltmeter having a resistance of 5 k?
B. Voltmeter having a sensitivity of 1 kW/V
C. Voltmeter having sensitivity of 10 kW/V
D. None of the above

3. A dynamometer wattmeter is connected in ac circuit. The reading will be
Options
A. V-A product
B. average power
C. peak power
D. instantaneous power

4. A meter with a resistance of 100 ? and a full scale deflection of current of 1 mA is to be converted into voltmeter of 0 - 5 V range. The multiplier resistance should be
Options
A. 490 ?
B. 5000 ?
C. 4900 ?
D. 5100 ?

5. A dynamometer wattmeter is connected in ac circuit. The measured power is
Options
A. rms power
B. average power
C. peak power
D. instantaneous power

6. In a thermocouple temperature transducer, the output voltage is usually measured by
Options
A. high resistance ammeter
B. high resistance voltmeter
C. high resistance milli-voltmeter
D. none of the above

7. A digital frequency counter can be converted to DVM by addition of a suitable
Options
A. voltage controlled oscillator
B. D/A converter
C. power amplifier
D. operational amplifier

8. Assertion (A): When a wattmeter is used for low impedance loads, the pressure coil is connected across the load.
Reason (R): A wattmeter measures apparent power.
Options
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true but R is not correct explanation of A
C. A is true R is false
D. A is false R is true

9. In which of the transformer is the secondary nearly short circuited under normal operating conditions?
Options
A. CT
B. PT
C. Distribution transformer
D. Power transformer

10. A single phase energy meter has the rating 1200 resolutions/ kWh. If a 500 W electric gadget is used for 4 hours, the energy meter will make
Options
A. 1200 revolutions
B. 1800 revolutions
C. 2100 revolutions
D. 2400 revolutions

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