Measurements And Instrumentation

Exercise: Measurements And Instrumentation

Assertion (A): Thermocouple instruments can be used for ac only.

Reason (R): Thermocouple instrument has a non linear scale.

Both A and R are true and R is correct explanation of A

Both A and R are true but R is not correct explanation of A

A is true R is false

A is false R is true

Answer: D

Thermocouple Instrument can be used for both ac and dc.

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The percentage limiting error in an instrument reading 8.3 V and having guaranteed accuracy of 1% of the full scale reading and range of 0-150 V is

1.81%

0.181%

18.1%

0.0018%

Answer: C

Error = 1% of 150 = 1.5 V,

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If the secondary winding of CT is opened when primary coil is carrying current

transformer will burn immediately

there will be weak flux density in core

there will be very high induced voltage in secondary

there will be high current in secondary

Answer: C

Since the primary of CT always remains excited, a high voltage is induced in secondary if the secondary is opened.

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Assertion (A): In loss of charge method, it is preferable to use an electronic voltmeter.

Reason (R): The resistance of electronic voltmeter is very high.

Both A and R are true and R is correct explanation of A

Both A and R are true but R is not correct explanation of A

A is true R is false

A is false R is true

Answer: A

If resistance of voltmeter is not high, accuracy is affected.

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It is required to study transients during switching process. Which CRO should be preferred?

Ordinary CRO

Dual beam CRO

Dual trace CRO

Storage oscilloscope

Answer: D

We can store the trace.

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