Electric Drives and Motors MCQ Part-9

Paramhans March 10, 2021

1. The colour temperature of daylight is about_________.

a. 100 K

b. 200 K

c. 500 K

d. 600 K 


2. Sky appears blue due to__________.

a. Scattering of light over dust particles

b. Refraction

c. Reflection

d. Radiation


3. Colour of light depends upon__________.

a. Velocity of light

b. Wavelength

c. Frequency

d. Both (b) and (c)

 

4. Luminous flux is __________.

a. Measured in flux

b. The part of light energy, radiation by sun that is received on earth

c. The rate of energy radiation in the form of light waves

 

5. Glare is caused due to_________.

a. Excessive lighting contrast in the field of vision

b. Excessive luminance

c. Either (a) or (b)

 

6. A perfect diffuser surface is one that_________.

a. Diffuses all the incident light

b. Absorbs all the incident light

c. Transmits all the incident light

d. All of the above

 

7. Which of the following material is most commonly used for the filaments in incandescent lamps ?

a. Silver

b. Tantalum

c. Osmium

d. Tungsten

 

8. Zero watt lamps consumes a power of _______.

a. Zero watt

b. 5-10 watt

c. About 15 W

d. About 25 W


9. The output of a tungsten filament depends on_______.

a. Temperature of filament

b. Size of the lamp

c. Size of the shell

d. All the above


10. An electric bulb, when broken, produces a bang. It is on account of ______.

a. Pressure of air in the bulb

b. Pressure inside is equal to that outside

c. Vacuum inside the bulb

d. None of the above


11. Filament lamps normally operate at a power factor of________.

a. 0.5 lagging

b. 0.8 lagging

c. 0.85 leading

d. Unity

 

12. Which gas is sometimes used in filament lamps ?

a. Krypton

b. Argon

c. Carbon dioxide

d. Nitrogen


13. The gas used in a gas-filled filament lamp is________.

a. Ozone

b. Nitrogen

c. Oxygen

d. Helium


14. In filament lamps, coiled coil filaments are used in________.

a. Higher wattage lamps

b. Low wattage lamps

c. Gas-filled lamps

d. Coloured lamps


15. In electric discharge lamps, light is produced by________.

a. Ionisation in a gas or vapour

b. Cathode ray emission

c. Heating effect of current

d. Magnetic effect of current


16. Glow lamps__________.

a. Cannot withstand shocks

b. Draw more power

c. Have cold cathode

d. Have hot cathode

 

17. When a sodium vapour lamp is switched on, initially the colour is_______.

a. Blue

b. Yellow

c. Pink

d. Red


18. An auto-transformer used with a sodium vapour lamp should have________.

a. High resistance

b. High leakage reactance

c. High step-down ratio

d. High step-up ratio


19. Phosphor zinc silicate produces light of________.

a. Yellow colour

b. Red colour

c. Green colour

d. Pink colour


20. A mercury vapour lamp gives light of _________.

a. Red  colour

b. Greenish-blue colour

c. Yellow colour

d. Pink colour


21. Neon lamps__________.

a. Are used as indicator lamps, night lamps, for determination of polarity of dc mains

b. Have power consumption of the order of 5 watts

c. Are of the size of ordinary incandescent lamps

d. All the above

 

22. In neon signs argon gas is used to give_________.

a. Green colour

b. Pink colour

c. Blue colour

d. Red colour

 

23. Neon tubes are widely used for_________.

a. Airport lighting

b. Road signaling

c. Indoor lighting

d. Advertising

 

24. The vapour discharge tube used for domestic light has________.

a. No filament

b. Four filaments

c. Two filaments

d. One filament


25. A stabilising choke is connected in the fluorescent tube circuit so as to __________.

a. Avoid radio-interference

b. Act as a starter

c. Act as a ballast in operating conditions and provide a voltage impulse for starting

d. Reduce the flicker


26. A capacitor is connected across the fluorescent tube circuit in order to __________.

a. Improve the power factor of the tube circuit

b. Limit the current

c. Eliminate the noise

d. All the above



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