Test
BSNL TTA ONLINE TEST - 4 Instruments and Measurements
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Preguntas del test (30)
1Which one of the following meters has maximum loading effect on the circuit under measurement ?
- A1000 Ω/volt
- B10 MΩ/volt
- C100 Ω/volt
- D1 MΩ/volt
2A 150 V moving iron voltmeter of accuracy class 1.0 reads 75 V when used in a circuit under standard conditions. The maximum possible percentage error in the reading is
- A0.5
- B1.0
- C2.0
- D4.0
3To measures 5 volts, if one selects a 0-100 volt range voltmeter which is accurate with in ± 1%, then the error in this measurement may be up to
- A10 %
- B20 %
- C30 %
- D40 %
4Assertion (A) : It is always desirable to take the reading of an indicating instrument very close to the full scale reading.
Reason (R) : Accuracy of an indicating instrument is maximum at the full scale deflection and error increases as reading comes closer to the beginning of the scale.- AA is true but R is false
- BA is false bur R is true
- CBoth A and R are true and R is the correct explanation of A
- DBoth A and R are true but R is NOT the correct explanation of A
5If an ammeter is to be used in place of a voltmeter, we must connect with the ammeter a
- AHigh resistance in parallel
- BHigh resistance in series
- CLow resistance in parallel
- DLow resistance in series
6In eddy current damping system, the disc employed should be of
- AConducting and magnetic material
- BConducting but non-magnetic material
- CMagnetic but non-conducting material
- DNon-conducting and non-magnetic material
7Which of the following can act as in inverse transducer?
- ALVDT
- BStrain
- CPiezo electric crystal
- DBimetal strip
8The total current I = I1 + I2 in a circuit is measured I1 = 150 ± 3A , I2 = 250 ± 4 A, where the limits of error are given as standard deviations. I is measured as
- A(400 ± 3) A
- B(400 ± 2.24) A
- C(400 ±5) A
- D(400 ± 1) A
9A first order instrument is characterized by
- AStatic sensitivity and damping coefficient
- BTime constant only
- CStatic sensitivity and time constant
- DStatic sensitivity, damping coefficient and natural frequency of oscillations
10The ratio of change in output to the change in the input is called
- Aprecision
- Bresolution
- Csensitivity
- Drepeatability
11The difference between the indicated value and the true value of a quantity is
- ADynamic error
- BGross error
- CAbsolute error
- DRelative error
12Which one the following statements is correct ?
The application of the instrument in wrong manner in the procedure of measurement results in a/an- Ainstrument error
- Brandom error
- Csystematic error
- Dgross error
13Two capacitance, C1 = 150 ± 2.4µF and C2 = 120 ± 1.5 µF are connected in parallel. What is the limiting error of the resultant capacitance C (in µF) ?
- A3.9µF
- B2.4µF
- C1.5µF
- D0.9µF
14Dynamic errors are caused by
- Ainstrument not responding fast
- Bhuman error
- Cenvironmental error
- Dobservational error
15Consider the following statements :
In a measuring instrument,
1. Linearity is more important than sensitivity.
2. High precision indicates high accuracy
3. Accuracy cannot be better than resolution.
Of these statements- A1 and 3 are correct
- B1 and 2 are correct
- C1, 2 and 3 are correct
- D2 and 3 are correct
16A resistance is measured by the voltmeter-ammeter method employing dc excitation and a voltmeter of very high resistance connected directly across the unknown resistance. If the voltmeter and ammeter reading are subject to maximum possible errors of ± 2.4 % and ± 1.0 % respectively, then the magnitude of the maximum possible percentage error in the value of resistance deduced from the measurement is nearly
- A± 1%
- B± 2.4%
- C± 3.4%
- D± 1.4%
17Two meters X and Y require 40 mA and 50 mA, Respectively, to give full-scale Deflection, then
- Asensitivity can not be judged with given information
- Bboth are equally sensitive
- CX is more sensitive
- DY is more sensitive
18Assertion (A) : Precision is a necessary prerequisite of accuracy.
Reason (R) : Precision guarantees accuracy.- AA is true but R is false
- BA is false bur R is true
- CBoth A and R are true and R is the correct explanation of A
- DBoth A and R are true but R is NOT the correct explanation of A
19An ammeter of range 0-25 A has a guaranteed accuracy of 1% of full-scale reading. The current measured by the ammeter is 5 A. The limiting error in the reading is
- A3 %
- B4 %
- C5 %
- D6 %
20Which of the following meter is most suitable for measuring radio frequency currents?
- AMoving - coil meter.
- BMoving - iron meter.
- CThermocouple meter.
- DVTVM.
21Schering bridge is used to measure which of the following ?
- AFrequency.
- BInductance.
- CCapacitance.
- DResistance.
22A moving coil of a meter has 100 turns, and a length and depth of 10 mm and 20 mm respectively. It is positioned in a uniform radial flux density of 200 mT. The coil carries a current of 50 mA. The torque on the coil is
- A200 µNm.
- B100 µNm.
- C400 µNm.
- D500 µNm.
23Attraction and repulsion type instruments are the two different types of which instrument ?
- AMoving iron type.
- BMultipliers.
- CDynamo-meter type.
- DInduction type.
24A PMMC voltmeter is connected across a series combination of a DC voltage source V1 = 2 V and an AC voltage source V2 = 3sin4t, the voltmeters reads
- A2 V
- B5 V
- C2+ 3sin4t
- D0 V
25An average reading digital multimeter reads 10 V when fed a triangular wave, symmetric about the axis. For the same input, an rms reading meter will read
- A20√3.
- B10√3.
- C10.
- D20.
26The effect of stay megnetic fields on the actuating torque of a portable instrument is maximum when the operating field of the instrument and stay fields are
- AInclined at 30°.
- BInclined at 60°.
- CParallel.
- DPerpendicular.
27Kelvines double bridge is used to measure low resistance because
- AThere is no thermo electric emf.
- BIt has high sensitivity.
- CEffect of contact and lead resistance is eliminated.
- DResistance variation due to temperature.
28An electrodynamic meter can be used to measure
- AAC volatge.
- BDC voltage.
- Cboth AC and DC voltage.
- DDC current.
29The main advantage of Anderson bridge over Maxwell bridge is that
- Areduction of the cost.
- Bbalance equation independent of frequency.
- Cattaining balance condition is easier.
- Dmeasures high Q inductors.
30Assertion(A): A low power factor wattmeter has special constructional features to ensure accurate measurment.
Reason(R): Extension of wattmeter range in DC circuit can be easily done by using current and potential trnasformer- AA is false R is true.
- BA is true R is false.
- CBoth A and R is true and R is correct explanation of A C.
- DBoth A and R is true and R is not correct explanation of A.
Información
- Descripción
- Subject : Instruments and Measurements Instruction: Time limit for the exam: 25 Minutes Total number of questions : 30 Q Each question carry 1 mark, no negative marks. DO NOT refresh the page. All the best by BSNL ACADEMY If U Like Our Test series than Share with your friends and Rate Our Tests.
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- BSNL ACADEMY
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- English
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