1. Radiant efficiency of the luminous source depends
on
(A)
shape of the source
(B)
temperature of the source
(C)
wavelength of light rays
(D)
all of the above.
Answer
: B
2. Light waves travel with a velocity of
(A)
3 x 1010cm/s
(B)
3 x 1012cm/s
(C)
3 x 1015 cm/s
(D)
3 x 1018 cm/s.
3. Carbon arc lamps are commonly used in
(A)
domestic lighting
(B)
street lighting
(C)
cinema projectors
(D)
photography.
Answer
: C
4. The unit of solid angle is
(A)
solid angle
(B)
radian
(C)
steradian
(D)
candela.
Answer
: C
5. Candela is the unit of
(A)
Luminous flux
(B)
Luminous intensity
(C)
Wavelength
(D)
None of the above.
Answer
: B
6. The unit of luminous flux is
(A)
steradian
(B)
candela
(C)
lumen
(D)
lux.
Answer
: C
7. The illumination is directly proportional to the
cosine of the angle made by the normal to the illuminated surface with the
direction of the incident flux. Above statement is associated with
(A)
Planck's law
(B)
Macbeth's law of illumination
(C)
Bunsen's law of illumination
(D)
Lambert's cosine law.
Answer
: D
8. Melting temperature of tungsten is
(A)
2000°K
(B)
2500°K
(C)2655°K
(D)
3655°K.
Answer : D
9. Illumination level required for precision work is
around
(A)
50 lm/m2
(B)
100 lm/m2
(C)
200 lm/m2
(D)
500 lm/m2.
Answer
: D
(A)
Guilds Flicker Photometer
(B)
Lummer Brodhun Photometer
(C)
Macbeth
(D)
Trotter Illumination Photometer.
Answer : C
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11. The color temperature of day light is around
(A)
50 K
(B)
160 K
(C)
600 K
(D)
6000 K.
Answer
: D
12. 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 : C
13. Lumen/watt is the unit of
(A)
Light flux
(B)
Luminous intensity
(C)
Brightness
(D)
Luminous efficiency.
Answer : D
14. Candela is-the unit for
(A)
Light flux
(B)
Luminous intensity
(C)
Brightness
(D)
Luminous efficiency.
Answer : B
15. Which of the following will need the highest level
of illumination ?
(A)
Proof reading
(B)
Bed rooms
(C)
Hospital wards
(D)
Railway platforms.
Answer
: A
16. Which of the following will need lowest level of
illumination ?
(A)
Displays
(B)
Fine engraving
(C)
Railway platform
(D)
Auditoriums.
Answer
: C
17. Which of the following lamp gives nearly
monochromatic light ?
(A)
Sodium vapor lamp
(B)
GLS lamp
(C)
Tube light
(D)
Mercury vapor lamp.
Answer
: A
18. The illumination level in houses is in the range
(A)
10-20 lumen/m2
(B)
30 - 50 lumen/m2
(C)
40-75 lumen/m2
(D)
100-140 lumen/m2.
Answer
: D
19. Luminous efficiency of a fluorescent tube is
(A)
5- 10 lumens/watt
(B)
15-20 lumens/watt
(C)
30 - 40 lumens/watt
(D)
60 - 65 lumens/watt.
Answer
: D
20. One lumen per square meter is the same as
(A)
One lux
(B)
One candela
(C)
One foot candle
(D)
One lumen meter.
Answer
: A
