INTERNATIONAL INSTITUTE OF MANAGEMENT & TECHNICAL STUDIES
QUESTION PAPER:MECHANICAL MEASUREMENT Max Marks:100
Note: Question number 1-5 carries 2 Marks Question number 6-15 carries 3 Marks Question number 16-20 carries 12 Marks
Q.1. Operating torques in analogue instruments are(a) deflecting and control(b) deflecting and damping(c) deflecting, control and damping(d) vibration and balancing
Q.2. An instrument transformer is used to extend the range of(a) induction instrument(b) electrostatic instrument(c) moving coil instrument(d) any of the above
Q.3. A power factor meter is based on the principle of(a) electrostatic instrument(b) Electrodynamometer instrument(c) Electro thermo type instrument(d) Rectifier type instrument.
Q.4.When using the terms “accuracy” and “precision” for measurementsa. “precision” implies less measurement error than “accuracy”b. “accuracy” implies less measurement error than “precision”c. “precision” measures the repeatability of a measurementd. both terms mean the same thing
Q.5. The bridge method commonly used for finding mutual inductance is(A) Heaviside Campbell bridge(B) Schering bridge(C) De Sauty bridge(D) Wien bridge
Q.6. The Q-meter works on the principle of(A) mutual inductance(B) self inductance(C) series resonance(D) parallel resonance
Q.7. A digital-to-analog converter with a full-scale output voltage of 3.5 V has a resolutionclose to 14 mV. Its bit size is(A) 4(B) 8(C) 16(D) 32
Q.8.Which of the following has the best accuracy(A).MI meter(B).Moving coil meter(C).Rectifier type meter(D).Thermocouple meter
Q.9.A 0-10 A ammeter has a guaranteed accuracy of 1% of FSD.The limiting error whilereading 2.5A(A).1%(B).2%(C).4%(D).none of the above
Q.10.In a transducer the observed output deviates from the correct value by constant factorthe resulting error is called(A).Zero Error(B).Sensitivity Error(C).Non-confirmity Error(D).Hysteresis error
Q.11. If the current in a capacitor leads the voltage by 80°, the loss angle of the capacitor is(a) 10°(b) 80°(c) 120°(d) 170°
Q.12. To avoid the effect of stray magnetic field in A.C. bridges we can use(a) magnetic screening(b) Wagner earthing device(c) wave filters(d) any of the above
Q.13. The disc of an instrument using eddy current damping should be of(a) conducting and magnetic material(b) non-conducting and magnetic material(c) conducting and non-magnetic material(d) none of the above
Q.14. An induction meter can handle current upto(a) 10 A(b) 30 A(c) 60 A(d) 100 A
Q.15. Which of the following devices may be used for extending the range of instruments ?(a) Shunts(b) Multipliers(c) Current transformers(d) Potential transformers(e) All of the above
Q.16(A). The inductance of moving iron ammeter in micro henry is given by expression:L=20+5θ-2θ2Where θ is deflection in radians from the zero position. Determine the angular in radians for a current of 10A if the for a current of 5A is 300.Also determine the spring constant.
Q.16(B).Derive the general torque equation for a MI instruments ?
Q.17(A).Explain the wattmeter errors in brief?
Q.17(B).For a certain electrodynamometer ammeter the mutual inductance M varies with the deflection of θ as M=-6cos(θ+300)mHFind the deflecting torque produced by the direct current of 50mA corresponding to the deflection of 600.
Q.18(A). A 220V,10A dc energy meter is tested at its marked ratings. The resistance ofpressure coil is 9900ohm and that of current coil is 0.5ohm .Calculate the power consumed when testing the meter with(i).Direct loading arrangements(ii).Phantom loading with current circuit excited by a 6V battery
Q.18(B). Draw the Maxwell’s bridge and give the balance equation.
Q.19.Power in a dc circuit is calculated as the product of current and voltage if the value of current and voltage are given by 6.3A and 110.2V and the uncertainities involved in their measurement being 0.06A and 0.1V .Calculate the power dissipated by the loads and the uncertainity involved in measurement.
Q.20(A).Explain the measurement of pressure using transducer.
Q.20(B).Explain the method use to measure high resistance.
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