Electrical and Electronics Measurement Mcq Questions

1. A CRO screen has 10 divisions on the horizontal scale. If a voltage signal 5 sin (314 t + 45°) is examined with a line base setting of 5 ms/division, the number of cycles of signal displayed on the screen will be

(a) 0.5 cycle
(b) 2.5 cycles
(c) 5 cycles.
(d) 10 cycles.

2. A non-triggered oscilloscope

(a) has a continuously running time-base generator.
(b) has no sweep generator.
(c) cannot produce a stable stationary screen display.
(d) can display a portion of the input signal waveform.

3. The oscilloscope has an input capacitance of 50 pF and a resistance of 2 MΩ and the voltage divider ratio (k) of 10. What are the parameters of a high-impedance probe?

(a) C₁ = 5.55 pF and R₁ = 9 MΩ.
(b) C₁ = 5.55 pF and R₁ = 18 MΩ
(c)C₁ = 3.33 pF and R₁ = 9 MΩ
(d) C₁ = 1.11 pF and R₁ = 18 MΩ

4. In a dual beam oscilloscope

(a) there are two separate vertical inputs and two separate horizontal inputs.
(b) there are two separate vertical inputs and there is only one set of horizontal deflection plates.
(c) there is only one vertical input but there are two separate horizontal deflection plates.
(d) there is only one vertical and one horizontal input.

5. A dual trace oscilloscope is set to operate in the alternate mode. The control input of the multiplexer used in the y-circuit fed with a signal having a frequency equal to

(a) the highest frequency that the multiplexer can operate properly.
(b) twice the frequency of the time base (sweep) oscillator.
(c) the frequency of the time bate (sweep) oscillator.
(d) half the frequency of the time base (sweep) oscillator.

6. Which of the following statements is NOT correct for a storage type oscilloscope ?

(a) The storage target is a conductive mesh covered with magnesium fluoride.
(b) Secondary emission electrons etch a positively charged pattern.
(c) The flood guns used for display, emit high velocity electrons.
(d) The flood guns are placed between the deflection plates and storage target.

7. If the transients during switching of power supply are to be studied, which oscilloscope will be preferred ?

(a) An ordinary oscilloscope with high frequency sweep generator.
(b) Dual beam oscilloscope.
(c) Dual trace oscilloscope.
(d) Storage oscilloscope.

8. Which of the following A/D converter is used in a Digital Storage Oscilloscope (DSO) ?

(a) Ramp type.
(b) Successive approximation type.
(c) Dual slope type.
(d) Parallel type.

9. A single channel digital storage oscilloscope uses a 12 bit, 10⁸ samples per second ADC. For a 10 kHz sine wave input, what is the number of samples taken per cycle of input ?

(a) 10¹²
(b) 10⁸
(c) 10⁴
(d) 10²

10. A single channel digital storage oscilloscope uses a 10 bit 10⁷ samples per second analog-to-digital converter. For a 100 kHz sine wave input, the number of samples taken per cycle of the input will be

(a) 10⁷
(b) 10⁴
(c) 10³
(d) 10²

11. Sampling oscilloscopes are specially designed to measure

(a) very low frequency.
(b) very high frequency.
(c) microwave frequency.
(d) none of the above.

12. In dc coupling mode, CRO can measure

(a) ac voltage only.
(b) dc voltage only.
(c) both ac and dc voltages.

13. The best method for testing waveforms of a TV receiver is to use an oscilloscope with

(a) open test leads.
(b) a shielded test cable.
(c) a low capacitance probe.
(d) none of the above.

14. Which one of the following is the correct statement ? Active probe used in a CRO

(a) is bulkier than passive ones.
(b) cannot measure small signals.
(c) cannot couple high frequency signals.
(d) can attenuate more.

15. A compensated probe of a CRO contains which of the following

1. An amplifier
2. R-C network
3. Only resistive network .
4. Only capacitive network

Select the correct answer using the code given below :
(a) 1 and 2 only.
(b) 2 only.
(c) 3 only.
(d) 4 only.

16. If the bandwidth of an oscilloscope is given as direct current to 10 MHz, what is the fastest rise time a sine wave can have to be produced accurately by the oscilloscope?

(a) 35 nsec.
(b) 10 nsec.
(c) 3.5 nsec.
(d) 0.035 nsec.

17. In distortion factor meter, the filter is used to suppress

(a) dc component.
(b) odd harmonics.
(c) even harmonics
(d) fundamentals.

18. The level range of harmonic analyzer using crystal filter is from

(a) – 90 dB to 32 dB
(b) 20 dB to 10 dB
(c) 40 dB to 90 dB
(d) 90 dB to 180 dB

19. A wave analyzer is basically a superheterodyne receiver covering the following range of frequency with an IF of 100 kHz.

(a) 20 Hz to 50 kHz
(b) 100 kHz to 1 MHz
(c) 5 MHz to 5 GHz
(d) 100 kHz to 100 GHz

20. Spectrum analyzer is a combination of

(a) narrowband superheterodyne receiver and CRO.
(b) signal generator and CRO.
(c) oscillator and wave analyzer.
(d) VTVM and CRO.

21. Which one of the following truly represents the output on the screen of spectrum analyzer when an amplitude modulated wave is connected to it ?

(a) Single vertical lines on the screen.
(b) Two vertical lines on the screen.
(c) Three vertical lines with amplitude.
(d) Three vertical lines out of which two have equal magnitude.

22. The dynamic range of a spectrum analyzer with a third order incept point of + 25 dB and a noise level of – 85 dB is

(a) 110 dB
(b) – 60 dB
(c) + 25 dB
(d) 73 dB