Measurement MCQs Part-10

Measurement MCQs

Cathode ray oscilloscope (CRO) Multiple choice questions

1. Post deflection acceleration is used to_________.

a. Focus the beam

b. Increase the velocity of the electron beam

c. Repel the electron beam

d. Enhance the intensity of the beam

 

2. The function of the synchronization section in CRO is_________.

a. To match the horizontal sweep rate with the frequency of the vertical signal

b. To control the gain of the amplifier

c. To start the horizontal sweep at the same relative point on the vertical signal

d. To adjust the intensity control

 

3. The distance between two peaks measured on the X-axis is 2 cm, at 1 ms/div. The frequency of the signal is__________.

a. 500 Hz

b. 1 kHz

c. 50 Hz

d. 5 kHz

 

4. A dual trace CRO uses__________.

a. Two pairs of HDPs

b. Two electron gun

c. One electron gun

d. None of these

 

5. A sampling CRO is used for_________.

a. Low frequencies

b. Very high frequencies

c. Very low frequencies

d. High frequencies

 

6. A time base selector basically consists of___________.

a. Wein bridge oscillator

b. Crystal oscillator

c. RC oscillator

d. LC oscillator

 

7. Trigger pulses in the CRO are used_________.

a. To synchronise the input and the vertical amplifier

b. To generator, high voltage required for the CRT

c. To synchronise the input with the time base generator

d. To generate low voltage required for the CRT

 

8. During the retrace time, the electrons forming the horizontal beam_________.

a. Move from bottom to top of screen

b. Move from top to bottom of screen

c. Move from left to right on the screen

d. Move from right to left on the screen

 

9. Post accelerate is needed in a CRO if the frequency of the signal is__________.

a. More than 10 MHz

b. More than 10 Hz

c. More than 1 MHz

d. Less than 1 MHz

 

10. The function of a delayed-sweep feature in many laboratory-quality oscilloscope is________.

a. To measure waveform jitter or rise time

b. To magnify a selected portion of the undelayed sweep

c. Both (a) and (b)

d. None of the above

 

11.  An electronic switch is used in a __________.

a. Sampling CRO

b. Single beam CRO

c. Dual beam CRO

d. Dual trace CRO

 

12. Spectrum analyser is a combination of___________.

a. VTVM and CRO

b. Oscillator and wave analyser

c. Signal generator and CRO

d. Narrowband superheterodyne receiver and CRO

 

13. Which of the following statements correctly represents the post acceleration in a cathode-ray tube?

a. It increase the brightness of the trace of low frequency signal

b. It accelerate the beam before deflection

c. It increase the brightness of the trace if the signal frequency is higher than 10 MHz

d. It provides deflection of the beam

 

14.  To the y-input of a CRO a signal defined by 10 sin 100t is applied. To the x-input, the signal 10 cos 100t is fed. The gain for both x-channel and y-channel is the same. The screen shows______.

a. A circle

b. An ellipse

c. A straight line

d. A sinusoidal signal

 

15. What is the maximum velocity of the beam of electrons in a CRT having a cathode-anode voltage of 800 V?

Assume the electrons to leave the cathode with zero velocity.

a. 86 km/s

b. 25 m/s

c. 22.2 km/s

d. 16.8 m/s