[1000(s+5)]/[s2(s+2)(s+25)]

Basic Electronics Objectives Part-2[1] Wien bridge oscillator can typically generate frequencies in the range ofa. 1kHz - 1 Mhzb. 1 Mhz - 10MHzc. 10MHz - 100MHzd. 100MHz - 150MHz

Ans: A[2] A differential amplifier, amplifiesa. and mathematically differentiates the average of the voltages on the two input linesb. and differentiates the input waveform on one line when the other line is groundedc. the difference of voltages between the two input linesd. and differentiates the sum of the two input waveform

Ans: C[3] The type of power amplifier which exhibits crossover distortion in its output is a. Class Ab. Class Bc. Class ABd. Class C

Ans: B[4] The lowest output impedance is obtained in case of BJT amplifiers fora. CB configurationb. CE configurationc. CC configurationd. CE with RE configuration

Ans: C[5] The upper cutoff frequency of an RC coupled amplifier mainly depends upona. Coupling Capacitorb. Emitter bypass capacitorc. Output capacitance of signal source

d. Inter-electrode capacitance and stray shunt capacitance

Ans: D[6] Just as a voltage amplifier amplifies signal voltage, a power amplifiera. amplifies powerb. amplifies signal currentc. merely converts the signal ac power into the dc powerd. merely converts the dc power into useful ac power

Ans: D[7]An oscillator of the LC type that has a split capacitor in the circuit isa. Hartly oscillatorb. Colpitts oscillatorc. Weinbridge oscillatord. R-C phase shift oscillator

Ans: B[8] The function of bleeder resistor in a power supply isa. the same as that of load resistorb. to ensure a minimum current drain in the circuitc. to increase the output dc voltaged. to increase the output current

Ans: B[9] In a bistable multivibrator circuit, commutating capacitor is useda. to increase the base storage chargeb. to provide ac couplingc. to increase the speed of responsed. to provide the speed of oscillations

Ans: C[10] Removing bypass capacitor across the emitter-leg resistor in a CE amplifier causes(A) increase in current gain.(B) decrease in current gain.(C) increase in voltage gain.(D)decrease in voltage gain.

Ans: D

Electrical Machines - Alternators : Part 8[1] Squirrel cage bars placed in the rotor pole faces of an alternator help reduce huntinga. above synchronous speed onlyb. below synchronous speed onlyc. above and blow synchronous speeds both

d. none of the above

Ans:  C[2] The stationary alternator should not be connected to live bus-bars because ita.  is likely to run as synchronous motorb. will get short - circuitedc. will decrease bus - bar voltage though momentarilyd. will disturb generated emf's of other alternators connected in parallel.

Ans: B[3] With a unity load p.f, the effect of armature reaction on the main field flux of an alternator isa. distortionalb. magnetisingc. demagnetisingd. nominal

Ans: A[4] At lagging loads, armature reaction in an alternator isa.   cross-magnetisingb.  demagnetisingc.  non-effectived.  magnetising

Ans: D[5] The frequency of voltage generated by an alternator having 4 poles and rotating at 1800 rpm isa. 60 Hzb. 7200 Hzc. 120 Hzd. 450 Hz

Ans: A[6] The main disadvantages of using short pitch winding in alternators is that ita. reduces harmonics in the generated voltageb. reduces the total voltage around the armature coilsc. produces asymmetry in the three phase windingsd. increases Cu of end connections.

Ans: B[7] Zero power factor method of an alternator is used to find itsa. efficiencyb. voltage regulationc. armature resistanced. synchronous impedance

Ans: B[8] Armature reaction in an alternator mainly affectsa. rotor speedb. terminal voltage per phasec. frequency of armature currentd. generated voltage per phase

Ans: D

[9]The effect of increasing air gap length in the induction motor will increase thea. power factorb. speedc. magnetising currentd. air gap flux

Ans: C[10] The principle of operation of a 3 phase induction motor is most similar to that of aa. synchronous motorb. repulsion start induction motorc. transformer with a shorted secondaryd. capacitor start, induction run motor

Ans: C

Power Electronics Objective Questions with Answers: Part-3[1] The breakdown mechanism in a lightly doped p-n junction under reverse biased condition is calleda. avalanche breakdownb. zener breakdownc. breakdown by tunnellingd. high voltage breakdown

Ans: A[2] For a large values of |VDS|, a FET behave asa. Voltage controlled resistorb. Current controlled current sourcec. Voltage controlled current sourced. Current controlled resistor

Ans: C[3] In a full wave rectifier without filter, the ripple factor isa. 0.482b. 1.21c. 1.79

d. 2.05

Ans: A[4] Space charge region around a P-N junctiona. does not contain mobile carriesb. contains both free electrons and holesc. contains one type of mobile carriers depending on the level of doping of the P or N regionsd. contains electrons only as free carriers

Ans: A[5] In a JFET, at pinch-off voltage applied on the gatea. The drain current becomes almost zerob. The drain current begins to decreasec. The drain current is almost at saturation valued. The drain to source voltage is close to zero volts

Ans: C[6] The value of ripple factor of a half wave rectifier without filter is approximatelya. 1.2b. o.2c. 2.2d. 2.0

Ans:A[7] In an intrinsic semiconductor, the Fermi-level isa. closer to the valence bandb. midway between conduction and valence bandc. closer to the conduction bandd. within the valence band

Ans: C[8] The transformer utilization factor of a half wave rectifier is approximatelya. 0.6b. 0.3c. 0.9d. 1.1

Ans: B[9] Transistor is a a. Current controlled current deviceb. Current controlled voltage devicec. Voltage controlled current deviced. Voltage controlled voltage device

Ans: AFor ex, the output current Ic depends on the input current Ib[10] If the output voltage of a bridge rectifier is 100V, the PIV of diode will bea. 100 * Square root(2) Vb. 200/(pi) Vc. 100 * (pi) Vd. 100/2 V

Ans: DPeak inverse voltage = max  secondary voltage = Vdc= 2Vm/pi = 100Vm = 100 * pi/2

Electrical Machine - DC Motor Objectives: Part 7[1] The basic requirement of a dc armature winding is that it must bea. a closed oneb. a lap windingc. a wave windingd. either b or c

Ans: A[2] The sole purpose of a commutator in a dc generator is toa. increase output voltageb. reduce sparking at brushesc. provide smoother outputd. convert the induced ac into dc

Ans: D[3] In small DC machines, armature slots are sometimes not made axial but are skewed, results ina. quieter operationb. slight decrease in lossesc. saving of copperd. both a and b

Ans: D[4] The critical resistance of the dc generator is the resistance ofa. armatureb. fieldc. loadd. brushes

Ans: B[5] In a dc generator, the generator, the generated emf is directly proportional to thea. field currentb. pole fluxc. number of armature parallel paths

d. number of dummy coils

Ans: B[6] The commutation process in a dc generator basically involvesa. passage of current from moving armature to a stationary loadb. reversal of current in an armature coil as it crosses MNAc. conversion of ac to dcd. suppression of reactance voltage

Ans:B[7] The essential condition for stable parallel operation of two dc generators having similar characteristics is that they should havea. same kilowatt output ratingsb. dropping voltage characteristicsc. same percentage regulationd. same no load and full load speed

Ans:B[8] An ideal dc generator has .......... voltage regulation.a. lowb. zeroc. positived. negative

Ans: B[9] Which generator has poorest voltage regulationa. seriesb. shuntc. compoundd. high

Ans: A[10] The voltage regulation of an over compound dc generator is alwaysa. Positiveb. negativec. zerod. high

Ans: B

Electrical Machines: Part 6[1] In a transformer the voltage regulation will be zero when it operates at(A) unity p.f.(B) leading p.f.(C) lagging p.f.(D) zero p.f. leading.

Ans: B

[2] In a stepper motor the angular displacement(A) can be precisely controlled.(B) it cannot be readily interfaced with micro computer based controller.(C) the angular displacement cannot be precisely controlled.(D) it cannot be used for positioning of work tables and tools in NC machines.

Ans: AExp: Stepper Motor - Introduction

[3] The power factor of a squirrel cage induction motor is(A) low at light load only.(B) low at heavy load only.(C) low at light and heavy load both.(D) low at rated load only.

Ans: A

[4] The generation voltage in India is usually(A) between 11 KV and 33 KV.(B) between 132 KV and 400 KV.(C) between 400 KV and 700 KV.(D) None of the above.

Ans: A

[5] When a synchronous motor is running at synchronous speed, the damper winding produces(A) damping torque.(B) eddy current torque.(C) torque aiding the developed torque.(D) no torque.

Ans: D

[6]If a transformer primary is energised from a square wave voltage source, its output voltage will be(A) A square wave.(B) A sine wave.(C) A triangular wave.(D) A pulse wave.

Ans: A

[7] A salient pole synchronous motor is running at no load. Its field current is switched off. The motor will(A) come to stop.(B) continue to run at synchronous speed.(C) continue to run at a speed slightly more than the synchronous speed.(D) continue to run at a speed slightly less than the synchronous speed.

Ans: B

[8] The frequency of the rotor current in a 3 phase 50 Hz, 4 pole induction motor at full load speed is about(A) 50 Hz.(B) 20 Hz.(C) 2 Hz.(D) Zero.

Ans: C

[9] The speed of a dc motor can be controlled by varyinga. its flux per poleb. resistance of armature circuitc. applied voltaged. all of the above

Ans: D

[10] Regarding Ward-Leonard system of speed control which statement is false?a. It is usually used where wide and very sensitive speed control is requiredb. It is used for motors having ratings from 750kW to 4000kWc. Capital outlay involved in the system is right since it uses two extra machinesd. It gives a speed range of 10:1 but in one direction onlye. It has low overall efficiency especially at light loads

Ans: D1.         The gain of a cascaded amplifier is equal to thea.         Product of individual gains.b.        Sum of individual gains.c.         Ratio of stage gains.d.        None of these.A

2.         Two stages of a multistage amplifier have gains of 50 and 20. The dB voltage gain isa.         3b.        30c.         300d.        1000D3.         The RC coupling is popular in audio amplifiers becausea.         It provides an output signal in phase with the input signal.b.        It needs low voltage collector supply.c.         It has better audio frequency response.d.        None of these.C4.         The major advantage of a direct coupled amplifier is thata.         It uses less number of components.b.        It has very good temperature stability.c.         It does no use frequency sensitive components.d.  It can amplify direct current and low frequencysignals.D5.         In a darlington pair,a.         Two transistors are connected in parallel.b.        The emitter if first transistor feeds the base of the second.c.         Collector of the first feeds the base of the second.B6.         Two identical stages of amplifers are cascaded by RC coupling. If 10 is the mid band voltage gain of each stage, the overall gain of the cascaded amplifier will be ……..dB.a.         40b.        100c.         20d.        20log1020A7.         In a multistage amplifier there are two or more stages – True.8.         The overall voltage gain of a multistage amplifier is obtained by adding the voltage gains of each stages when expressed as a voltage ratio –False [ In dB, the voltage gains are added. In ratio, they are multiplied]9.         When you connect an identical 2nd stage transistor amplifier to the first stage, the voltage gain of the first stage increases – The voltage gain of the first stage decreases.

10.      The lower cutoff frequency of a two stage RC coupled amplifier is higher than its value for the single stage amplifier – True.11.      By cascading the 2nd stage of an identical transistor amplifier, the upper cutoff frequency increases. – False – Upper cutoff frequency decreases.12.      In a multistage amplifier, the transformer coupling is used whenever we want to amplify very low frequency or dc signals. – False – To amplify low frequency or dc signals, direct coupling is used.13.      RC coupling is the best coupling scheme when frequency of the signal is in the range of 60Hz to 20KHz. – True.14.      In a multistage voltage amplifier transformer coupling is used to amplify audio signals – False – RC coupling is used.15.      We always use RC coupling for amplifying a small band of radio frequency (1400KHz to 1410KHz) signal – False – Transformer coupling is used.

16.      A radio receiver has ……of amplification.a.         One stage.b.        Two stages.c.         Three stages.d.        More than 3 stages.D17.      RC coupling is used for ……..amplification.a.         Voltage.b.        Current.c.         Power.d.        None.A18.      In an RC coupled amplifier, the voltage gain over mid frequency range …….a.         Changes abruptly with frequency.b.        Is constant.c.         Changes uniformly with frequency.d.        None.B19.      In obtaining the frequency response curve of an amplifier, thea.         Amplifier level output is kept constant.b.        Amplifier frequency is held constant.c.         Generator frequency is held constant.d.        Generator output level is held constant.D20.      An advantage of RC coupling scheme is the

a.         Good impedance matching.b.        Economy.c.         High efficiency.d.        None.B21.      The best frequency response is of …… coupling.a.         RCb.        Transformer.c.         Direct.d.        None.C22.      Transformer coupling is used for …….amplification.a.         Power.b.        Voltage.c.         Current.d.        None.A23.      In an RC coupling scheme, the coupling capacitor CC must be large enougha.         To pass dc between the stages.b.        Not to attenuate the low frequencies.c.         To dissipate high power.d.        None.B24.      In RC coupling, the value of coupling capacitor is abouta.         100pF.b.        0.1μFc.         0.01μFd.        10 μF.                                                                        D25.      The noise factor of an ideal amplifier expressed in dB isa.         0b.        1c.         0.1d.        10A26.      When a multistage amplifier is to amplify dc signal, then one must use ……..coupling.a.         RCb.        Transformer.

c.         Direct.d.        None.C27.      ………coupling provides the maximum voltage gain.a.         RCb.        Transformer.c.         Direct.d.        Impedance.B28.      In practice, voltage gain is expressed ………..a.         In dB.b.        In volts.c.         As a number.d.        None.                                                                        A29.      Transformer coupling provides high efficiency becausea.         Collector voltage is stepped up.b.        Dc resistance is low.c.         Collector voltage is stepped down.d.        None.B30.      Transformer coupling is generally employed when load resistance isa.         Large.b.        Very large.c.         Small.d.        None.C31.      If a three stage amplifier has individual stage gains of 10, 5 and 12dBs, then total gain in dB isa.         600dB.b.        24dB.c.         14dB.d.        27 dB.D32.      The final stage of a multistage amplifier uses …… coupling.a.         RCb.        Transformer.c.         Direct.d.        Impedance.B

33.      The ear is not sensitive toa.         Frequency distortion.b.        Amplitude distortion.c.         Frequency as well as amplitude distortion.d.        None.A34.      RC coupling is not used to amplify extremely low frequency becausea.         There is considerable power loss.b.  There is hum in the output.c.         Electrical size of coupling capacitor becomes very large.d.        None of the above.C35.      In transistor amplifier we use ……………transformer for impedance matching.a.         Step up.b.        Step down.c.         Same turns ratio.d.        None.B36.      The lower and upper cutoff frequencies are also called ……….. frequencies.a.         Sideband.b.        Resonant.c.         Half resonant.d.        Half power.D37.      A gain of 1000000 times in power is expressed by …….dB.a.         30b.        60c.         120d.        600B38.      A gain of 100 times in voltage is expressed by ……..dB.a.         60b.        30c.         120d.        600                                                                        A39.      1 dB corresponds to …………% change in power level.a.         50

b.        35c.         26d.        22C40.      1 dB corresponds to ………% change in voltage or current level.a.         40b.        80c.         20d.        25A41.      The frequency response of transformer coupling isa.         Good.b.        Very good.c.         Excellent.d.        Poor.D42.      In the initial stages of a multistage amplifier, we use ….coupling.a.         RCb.        Transformer.c.         Direct.d.        None.A43.      The total gain of a multistage amplifier is less than the product of the gains of individual stages due toa.         Power loss in the coupling device.b.        Loading effect of next stage.c.         The use of many transistors.d.        The use of many capacitors.                                                                        B44.      The gain of an amplifier is expressed in dB becausea.         It is a simple unit.b.        Calculations become easy.c.         Human ear response is logarithmic.d.        None.C45.      If the power level of an amplifier reduces to half, the dB gain will fall by …dB.a.         0.5b.        2c.         10

d.        3D46.      A current amplification of 2000 is a gain of ……….dB.a.         3b.        66c.         20d.        200B47.      An amplifier receives 0.1W of input signal and delivers 15W of signal power. What is the power gain in dB?a.         21.8b.        14.6c.         9.5d.        17.4A48.      RC coupling is generally confined to low power applications because ofa.         Large value of coupling capacitor.b.        Low efficiency.c.         Large number of components.d.        None.                                                                        B49.      The number of stages that can be directly coupled is limited becausea.         Changes in temperature cause thermal stability.b.        Circuit becomes heavy and costly.c.         It becomes difficult to bias the circuit.d.        None.A50.      The purpose of RC or transformer coupling is toa.         Block ac.b.        Separate bias from one stage from another.c.         Increase thermal stability.d.        None.B

1. An ideal amplifier hasa) Noise figure of 0 dbb) Noise figure of more than 0 dbc) Noise factor of unityd) Noise figure of less than 1 db Ans : (c)

2. Fidelity representsS1: Reproduction of signal

S2: Reproduction of phase relationa) S1 and S2 are trueb) S1 and S2 are falsec) S1 false and S2 trued) S1 true and S2 false Ans : (d)

3. The decibel is a measure ofa) Currentb) Voltagec) Powerd) Power level Ans : (d)

4. Power gain in decibels is equal to voltage gain in decibels only whena) Input impedance is equal to output impedanceb) Output impedance is zeroc) Neverd) Input impedance is zero Ans : (a)

5. If the current gain of the amplifier is X, its voltage gain is Y, then its power gain will bea) X/Yb) X*Yc) X+Yd) X-Y Ans : (b)

6. In an amplifier, the coupling capacitors are employed fora) Limiting the bandwidthb) Matching the impedancec) Preventing of Dc mixing with input or outputd) Controlling the output Ans : (c)

7. The amplifier which has no drift is called asa) Differential amplifierb) DC amplifierc) Single ended amplifierd) Chopper amplifier Ans : (d)

8. The amplifier gain varies with frequency. This happens mainly due toa) Miller effectb) Presence of external and internal capacitancec) Logarithmic increase in its outputd) Inter stage transformer Ans : (b)

9. The outstanding characteristics of a D.C. amplifier is itsa) Ability to amplify Dc and low frequency signalsb) Temperature stabilityc) Utmost economyd) Avoidance of frequency sensitive components Ans : (a)

10. Isolation amplifier actually operates on the principle ofa) Filteringb) Attenuationc) Clippingd) Amplification Ans : (b)

11. Isolation amplifiers are also called asa) DC amplifierb) Output amplifierc) Inverting amplifierd) Iso-amps Ans : (d)

12. The improper response time of the amplifier in the biomedical recordersa) Affects the gain of the amplifierb) Delays the signalsc) Changes the shape of the waveform of the signald) Attenuates the signals Ans : (c)

13. To reduce common mode interference during recording of bio signals one can use__________a) Buffer amplifierb) Differential amplifierc) Single ended amplifierd) Chopper amplifier Ans : (b)

14. Resistively generated inference arises through incorrect __________________a) Groundingb) Current density at the electrodesc) Supply voltaged) Input impedance Ans : (a)

15. CMRR is more in_______________a) Single ended amplifierb) Differential amplifierc) Inverting operational amplifierd) Chopper amplifier Ans : (b)

16. For biomedical applications the mostly used amplifier isa) Single ended amplifierb) Differential amplifierc) Inverting operational amplifierd) Chopper amplifier Ans : (b)

17. ___________ amplifier is used to drive the recorder.a) Power amplifierb) Pre amplifierc) Operational amplifierd) Differential amplifier Ans : (a)

18. When a number of components are fabricated on same IC chip it is necessary to provide isolation between two different components for input interconnection is called __________a) Input amplificationb) Input differentiationc) Common mode rejectiond) Input isolation Ans : (d)

19. A chopper amplifiera) Converts AC signal from low frequency to high frequencyb) Converts DC signal from low frequency to high frequencyc) Converts AC signal from low frequency to DC high frequencyd) Converts DC signal from low frequency to high frequency Ans : (b)

20. Power amplifier is provided withS1: Cross over distortion compensationS2: Offset controla) S1 is true & S2 is falseb) S2 is true & S1 is falsec) Both S1 & S2 are trued) Both S1 & S2 are false Ans : (c)

21. Pre amplifier isolation in ECG circuit is toa) Increase input impedanceb) Decrease input impedancec) Increase output impedanced) Decrease output impedance Ans : (a)

22. Raising input impedance of pre amplifier reducesa) Input currentb) Output currentc) Stray currentd) Grid current Ans : (c)

23. Common mode rejection ratio is defined as ratio ofa) Common mode gain to differential mode gainb) Differential mode gain to common mode gainc) Common mode gain at input to differential mode gain at inputd) Common mode gain at output to differential mode gain at output Ans : (b)

24. An electrometer amplifier has high input impedance ofa) 1010?b) 105?c) 1020?d) 1015? Ans : (d)

25. When the input of differential amplifier V1 = 0, then the differential amplifier is said to be operated ina) Common mode

b) Differential modec) Non inverting moded) Inverting mode Ans : (c)

26. When either one of the inputs to the differential amplifier is equal to zero then it is said to be operated ina) Single ended modeb) Differential modec) Non inverting moded) Inverting mode Ans : (a)27. The negative feed back in an amplifiera) Reduces voltage gainb) Increases the voltage gainc) Increases the gain band width productd) Reduces the input impedances Ans : (a)

28. Feedback in an amplifier always helps ina) Increasing its input impedanceb) Increasing its gainc) Controlling its outputd) Stabilizes its gain Ans : (c)

29. Using mechanical chopper we cannot achieve high chopping rates due to theira) Input impedanceb) Output impedancec) Response timed) Inertia Ans : (d)

30. The CMRR of a typical IC OPAMP isa) 70 dBb) 80 dBc) 85 dBd) 75 dB Ans : (b)

31. A ————– is usually a display device used to produce a paper record of analog wave form.a) Graphic pen recorderb) Electron microscopec) X-Y recorderd) Oscilloscope Ans : (a)

32. The _________ of a recording system is the magnitude of input voltage required to produce a standard deflection in a recorded trace.a) Accuracyb) Linearityc) Sensitivityd) Resolution Ans : (c)

33. A recorder is said to have good frequency response when the sensitivity of the system is _________ for all frequencies present in the signal.a) Unityb) Zeroc) Infinityd) Constant Ans : (d)

34. In phase response of a recorder noise level ___________ with the band width of a systema) Increasesb) Decreasesc) Reaches unityd) Reaches infinity Ans : (a)

35. Function of microscope isS1: To magnify object, under observationS2: To resolve the objecta) S1 is true & S2 is falseb) S2 is true & S1 is falsec) Both S1 & S2 are trued) Both S1 & S2 are false Ans : (c)

36. In electron microscope the projection of the motion on a plane normal to magneticinduction (B) will be a circle of radius (r) =a) mVsin?+eBb) mVsin?/eBc) mVsin?-eBd) mVsin?*eB Ans : (b)

37. Match the following1. Electron microscope – (A) Electron gun2. Oscilloscope – (B) Condensing magnetic lens3. Galvanometric recorder – (C) Recording head4. Magnetic recorder – (D) Drive motora) 1-A, 2-B, 3-C, 4-Db) 1-D, 2-C, 3-B, 4-Ac) 1-B, 2-A, 3-D, 4-Cd) 1-C, 2-D, 3-A, 4-B Ans : (c)

38. In PMMC writing system, the magnitude of pen deflection is proportional toS1: Current flowing through the coilS2: Voltage in the coila) S1 is true & S2 is falseb) S2 is true & S1 is falsec) Both S1 & S2 are trued) Both S1 & S2 are false Ans : (a)

39. Duration of rotation of pen in the PMMC system depends upon ___________a) Phase angleb) Frequencyc) Magnituded) Direction Ans : (d)

40. The shorter wave length of the electron permits the detailed examination of tiny objects due to reduction of ___________ effectsa) Reflectionb) Diffractionc) Refractiond) Polarization Ans : (b)

41. Which of the following recorder gives slow responsea) X-Y recorderb) Oscillographicc) Galvanometricd) Magnetic Ans : (c)

42. The use of storage oscilloscopeS1: Viewing rapidly changing non repetitive wave formsS2: Recording average valuesa) S1 is true & S2 is falseb) S2 is true & S1 is falsec) Both S1 & S2 are trued) Both S1 & S2 are false Ans : (b)

43. In X-Y recorders, the self balancing potentiometers plot emf as a function ofa) Another emfb) Frequencyc) Timed) Pressure Ans : (a)

44. In strip chart recorders, the self balancing potentiometers plot emf as a function ofa) Another emfb) Frequencyc) Timed) Pressure Ans : (c)

45. The slewing speed of X-Y recorder isa) 1.6 m/sb) 1.3 m/sc) 1.4 m/sd) 1.5 m/s Ans : (d)46. The resolution limit of electron microscope isa) 2 A.Vb) 1 A.V

c) 1.5 A.Vd) 1.2 A.V Ans : (b)

47. _____________ is also known as halftone storage or mersh storage.a) Variable persistence storageb) Bistable storagec) Flat storaged) CRT Ans : (a)

48. Storage oscilloscope operates on the principle ofa) Primary emissionb) Deflectionc) Secondary emissiond) Diffusion Ans : (c)

49. The writing speed of fast storage oscilloscope isa) 2000 cm/?sb) 1000 cm/?sc) 1500 cm/?sd) 2500 cm/?s Ans : (a)

50. Stress and strain curves are plotted usinga) Magnetic tape recordingb) X-Y recordingc) Galvanometricd) PMMC writing systems Ans : (b)