Electric Illumination MCQs

16. The standard wattage of 3 ft. fluorescent tube is

(A) 10 W
(B) 40 W
(C) 65 W
(D) 100 W.

Answer
Answer. B

17. For the same wastage which lamp is cheapest?

(A) Sodium vapor lamp
(B) Mercury vapor lamp
(C) Fluorescent tube
(D) GLS lamps.

Answer
Answer.D

18. Optical instruments used for the comparison of candle powers of different sources arc known as

(A) Candle meters
(B) Radio meters
(C) Bunsen meter
(D) Photo meter.

Answer
Answer.D

19. Which photometer is used for comparing the lights of different colours?

(A) Bunson photometer
(B) Grease spot photometer
(C) Lummer Brodhum photometer
(D) Guilds Flicker Photometer.

Answer
Answer. D

20. Which photometer depends for its operation on Lambert’s cosine law?

(A) Macbeth lllumino meter
(B) Trotter Illumination Photometer
(C) Lummer Brodhum Photometer
(C) Guild’s Flicker Photometer.

Answer
Answer. B

21. Which photometer depends for its operation on Inverse Square Law?

(A) Guilds Flicker Photometer
(B) Lummer Brodhum Photometer
(C) Macbeth llluminometer
(D) Trotter Illumination Photometer.

Answer
Answer. C

22. The colour temperature of day light is around

(A) 50 K
(B) 160 K
(C) 600 K
(D) 6000 K.

Answer
Answer. D

23. Light is produced in electric discharge lamps by

(A) heating effect of current
(B) magnetic effect of current
(C) ionization in a gas or vapor
(D) carbon electrodes.

Answer
Answer. C

24. Lumen/watt is the unit of

(A) Light flux
(B) Luminous intensity
(C) Brightness
(D) Luminous efficiency.

Answer
Answer. D

25. Candela is the unit for

(A) Light flux
(B) Luminous intensity
(C) Brightness
(D) Luminous efficiency

Answer
Answer. B

26. Which gas is sometimes used in filament lamps?

(A) Argon
(B) Krypton
(C) Nitrogen
(D) Carbon dioxide.

Answer
Answer. A

27. Which bulb operates on lowest power?

(A) Night bulb
(B) Neon bulb
(C) GLS bulb
(D) Torch bulb.

Answer
Answer. D

28. The output of a tungsten filament lamp depends on

(A) size of a lamp
(B) size of a shell
(C) the temperature of the filament
(D) all of the above.

Answer
Answer. C

29. A zero watt lamp consumes

(A) no power
(B) about 5 to 7 W power
(C) about 15 to W power
(D) about 25 to 30 W power.

Answer
Answer. B

30. Melting temperature of tungsten is

(A) 2000°K
(B) 2500°K
(C) 2655°K
(D) 3655°K.

Answer
Answer. D

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