MCQOPTIONS
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MCQOPTIONS
This section includes 36 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
High frequency (in the MHz range) and low amplitude (in the mV range) signals are best measured using |
| A. | VTVM with a high impedance probe |
| B. | CRO |
| C. | moving-iron instrument |
| D. | digital multimeter |
| Answer» C. moving-iron instrument | |
| 2. |
A CRT has an anode voltage of 2000 V and parallel deflecting plates 2 cm long and 5 mm apart. The screen is 30 cm from the centre of the plates. If the input voltage is applied to the deflecting plates through amplifiers having an overall gain of 100, the input voltage required to deflect the beam through 3 cm will be |
| A. | 7 V |
| B. | 3 V |
| C. | 5 V |
| D. | 1 V |
| Answer» E. | |
| 3. |
A dual-beam CRO |
| A. | has one set of vertical deflection plates |
| B. | has two sets of horizontal deflection plates |
| C. | has two separate electron beams |
| D. | None of the above |
| Answer» D. None of the above | |
| 4. |
CROs are used to measure frequencies up to ________. |
| A. | 20 kHz |
| B. | 1 GHz |
| C. | 1 MHz |
| D. | 20 Hz |
| Answer» C. 1 MHz | |
| 5. |
A CRO can display: |
| A. | D.C. signals only |
| B. | A.C. signals only |
| C. | Both D.C. and A.C. signals |
| D. | Time-invariant signals |
| Answer» D. Time-invariant signals | |
| 6. |
In a Cathode Ray Tube, the focusing anode is located |
| A. | After accelerating anode |
| B. | Between pre-accelerating and accelerating anode |
| C. | Before pre-accelerating anode |
| D. | Just after electron-guns |
| Answer» C. Before pre-accelerating anode | |
| 7. |
A cathode ray oscilloscope typically has an input impedance of. |
| A. | 1 GΩ |
| B. | 1 kΩ |
| C. | 1 MΩ |
| D. | 1 Ω |
| Answer» D. 1 Ω | |
| 8. |
Oscilloscopes are normally designed such that the product of bandwidth and rise time is: |
| A. | 0.65 |
| B. | 0.95 |
| C. | 1.15 |
| D. | 0.35 |
| Answer» E. | |
| 9. |
An oscilloscope displays a 50 Hz, 20 V peak-to-peak sine waveform. Identify the reading in a digital multimeter for the same signal. |
| A. | 35.35 V |
| B. | 7.07 V |
| C. | 6.36 V |
| D. | 10 V |
| Answer» D. 10 V | |
| 10. |
Loading by the measuring instruments introduces an error in the measured parameter. Which of the following devices gives the most accurate result? |
| A. | PMMC |
| B. | Hot-wire |
| C. | CRO |
| D. | Electrodynamic |
| Answer» D. Electrodynamic | |
| 11. |
A vertical amplifier for a CRO can be designed for _____. |
| A. | High gain |
| B. | Different gain |
| C. | Low gain |
| D. | Constant gain |
| Answer» E. | |
| 12. |
Aquadag coating is most commonly used in CROs to: |
| A. | absorb moisture |
| B. | absorb the extra electrons emitted |
| C. | absorb and emit the rays |
| D. | absorb the rays emitted |
| Answer» C. absorb and emit the rays | |
| 13. |
From the given Lissajous patterns obtained while measuring the frequency using a cathode-ray oscilloscope (CRO), the pattern while indicates the relationship \({f_v} = \frac{1}{2}{f_h}\) |
| A. | (c) |
| B. | (d) |
| C. | (b) |
| D. | (a) |
| Answer» D. (a) | |
| 14. |
An aquadag is used in a CRO to collect |
| A. | Primary electrons only |
| B. | Secondary emission electrons only |
| C. | Both primary electrons and secondary emission electrons |
| D. | Heat emission electrons |
| Answer» C. Both primary electrons and secondary emission electrons | |
| 15. |
A sinusoidal voltage is measured by CRO. The vertical distance between the positive and negative peaks is 8 cm. If the scale of the CRO is set at 5 mV/cm, then the peak value of voltage will be |
| A. | 20 mV |
| B. | 40 mV |
| C. | 5 mV |
| D. | 10 mV |
| Answer» B. 40 mV | |
| 16. |
In CRO, during retrace time the electron beam travel ______ from ______ of the screen. |
| A. | Diagonally _____ top left to bottom right |
| B. | Vertically _______ top to bottom |
| C. | Horizontally ________ right to left |
| D. | Vertically _____ bottom to top |
| Answer» D. Vertically _____ bottom to top | |
| 17. |
A CRO Screen has ten divisions on the horizontal scale. If a voltage signal 5 sin (314t + 45°) is examined with a line base setting of 5 msec/div, the number of cycle of signal displayed on the screen will be? |
| A. | 0.5 cycle |
| B. | 2.5 cycle |
| C. | 5 cycles |
| D. | 10 cycles |
| Answer» C. 5 cycles | |
| 18. |
Lissajous pattern shown in a double-beam cathode-ray oscilloscope screen for two sinusoidal voltages of equal magnitude and of the same frequency but of phase shift of 30° electrical is |
| A. | a circle |
| B. | a straight line at 45° |
| C. | an ellipse in the first and third quadrant |
| D. | an ellipse in the second and fourth quadrant |
| Answer» D. an ellipse in the second and fourth quadrant | |
| 19. |
In a two-channel oscilloscope operating in x-y mode, two in-phase 50 Hz sinusoidal waveforms of equal amplitude are fed to the two channels. What will be the resultant pattern on the screen? |
| A. | An ellipse |
| B. | A parabola |
| C. | Straight line inclined at 45° with respect to x-axis |
| D. | A circle |
| Answer» D. A circle | |
| 20. |
By using AC coupling mode in a CRO ________. |
| A. | any signal cannot be viewed on the display |
| B. | only AC signal can be viewed on the display |
| C. | only DC signal can be viewed on the display |
| D. | both AC and DC signals can be viewed on the display |
| Answer» C. only DC signal can be viewed on the display | |
| 21. |
If the bandwidth of an oscilloscope is 10 MHz, what is the fastest rise time a square wave can have to be accurately reproduced by the instrument? |
| A. | 10 ns |
| B. | 35 ns |
| C. | 28 ns |
| D. | 100 ns |
| Answer» C. 28 ns | |
| 22. |
In the ____ Storage Oscilloscope signals can be stored. |
| A. | Cathode ray tube (CRT). |
| B. | Digital Oscilloscope |
| C. | Analog Oscilloscope. |
| D. | VTVM |
| Answer» C. Analog Oscilloscope. | |
| 23. |
A sinusoidal waveform has peak-peak amplitude of 6 cm viewed on a CRO screen. The vertical sensitivity is set to 5V/cm. The RMS value of the signal is |
| A. | 15 V |
| B. | 12.6 V |
| C. | 21.2 V |
| D. | 10. 6 V |
| Answer» E. | |
| 24. |
In an oscilloscope, the sensitivity can be increased by _________ |
| A. | decreasing the value of accelerating voltage Ea |
| B. | increasing the value of accelerating voltage Ea |
| C. | increasing the separation between the deflecting plates |
| D. | None of these |
| Answer» B. increasing the value of accelerating voltage Ea | |
| 25. |
A 500 kHz waveform is to be displayed by Digital Storage Oscilloscope (DSO) that samples at a rate of 50 Ms/sec (50 Mega samples per second). The number of samples taken during one cycle is |
| A. | 10,000 |
| B. | 1,000 |
| C. | 0.01 |
| D. | 100 |
| Answer» E. | |
| 26. |
For a bandwidth of 100 MHz, oscilloscope should have a rise time of: |
| A. | 5.5 ns |
| B. | 7.5 ns |
| C. | 3.5 ns |
| D. | 9.5 ns |
| Answer» D. 9.5 ns | |
| 27. |
Match the following Lissajous figures to their vertical deflection voltage graph. |
| A. | 1 - d, 2 - b, 3 - c, 4 - a |
| B. | 1 - b, 2 - d, 3 - a, 4 - c |
| C. | 1 - a, 2 - d, 3 - b, 4 - c |
| D. | 1 - c, 2 - a, 3 - d, 4 - b |
| Answer» E. | |
| 28. |
Important elements of the sampling circuit of sampling oscilloscope are given below(a) Voltage comparator(b) Blocking oscillator(c) Staircase generator(d) Ramp generatorThe correct sequence of the above elements in the sampling circuit in the direction from trigger input to horizontal signal is |
| A. | (a), (b), (c), (d) |
| B. | (b), (d), (c), (a) |
| C. | (a), (b), (d), (c) |
| D. | (b), (d), (a), (c) |
| Answer» E. | |
| 29. |
An oscilloscope shows peak-to-peak amplitude of 8 cm for a measured sinusoidal voltage waveform with vertical sensitivity knob set to 4 V/cm. The average value of the voltage is: |
| A. | 40.74 V |
| B. | 10.19 V |
| C. | 2.55 V |
| D. | 20.37 V |
| Answer» C. 2.55 V | |
| 30. |
Calculate the fastest rise time (in ms) a sine wave can have to be reproduced by a CRO, if the bandwidth ranges from 0 Hz to 10 Hz. |
| A. | 17.5 |
| B. | 0.35 |
| C. | 35 |
| D. | 1.75 |
| Answer» D. 1.75 | |
| 31. |
An input voltage required to deflect a beam through 3 cm in a Cathode Ray Tube having an anode Voltage of 1000 V and parallel deflecting plates 1 cm long and 0.5 cm apart, when screen is 30 cm from the center of the plates is: |
| A. | 300 V |
| B. | 200 V |
| C. | 100 V |
| D. | 75 V |
| Answer» D. 75 V | |
| 32. |
Important elements of cathode ray tube are given below:a) Pre-accelerating anodeb) Accelerating anodec) Focusing anoded) Heated cathodeCorrect sequence of the above elements in a CRT in the direction of electron beam is |
| A. | a, b, c, d |
| B. | a, c, b, d |
| C. | d, a, c, b |
| D. | d, c, a, b |
| Answer» E. | |
| 33. |
Arrange the following in their order of occurance from control grid to fluorescent screen(A) Focusing Anode(B) Horizontal Deflection Plates(C) Aquadag(D) Pre-accelerating anode(E) Vertical deflection platesChoose the correct answer from the options given below:(1) (A), (D), (C). (B), (E)(2) (B), (C), (D). (A), (E)(3) (D), (A), (E). (B), (C)(4) (C), (B), (D). (E), (A) |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» D. 4 | |
| 34. |
Determine the bandwidth (in Hz) of a sine wave that is reproduced by a CRO having a rise time of 70 ms. |
| A. | 5 |
| B. | 10 |
| C. | 15 |
| D. | 20 |
| Answer» B. 10 | |
| 35. |
For displaying high frequency signals, cathode ray tube should have |
| A. | High persistence |
| B. | Focusing system |
| C. | Very high input impedance |
| D. | Provision for post deflection acceleration |
| Answer» E. | |
| 36. |
Determine the deflection sensitivity (in m/V) of a CRO, when the value of the deflection factor is 0.5 V/m. |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |