01.candela is the unit of which?
Wavelength.
Luminous
intensity.
Luminous
flux.
Frequency.
02․ Solid angle is expressed in terms of
radians
/ meter.
radians.
steredians.
degree.
03․ Which lamp has the best Colour Rendering Index (CRI)?
LED
Fluorescent
Incandescent
High
pressure sodium vapour
04․ Which cells in the eye are responsible for scotopic vision?
Cone
cells
Rod
cells
Both
‘a’ and ‘b’
None
of these
05․ What is the ratio of illuminance at
a point 5m just below a lamp emitting 100 candelas and at a point 5m away from
the first point on the same horizontal plane?
1:2
2√2
: 1
1:
2√2
2:1
06․ Which lamps can be directly connected to a solar cell?
Incandescent
Metal
Halide
Compact
Fluorescent
LED
07․ Candela/metre square is the unit of which photometric
quantity?
Illuminance
Luminous
flux
Luminance
Luminous
Intensity
08․ Which lamp is best suited for lighting an International
sports arena?
Incandescent
Metal
Halide
Compact
Fluorescent
LED
09․ What is the work of a driver in case of an LED?
To
convert AC to DC
To
convert DC to AC
Both
‘a’ and ‘b’
None
of these
10․ What will be the number of lamps, each having 300 lumens,
required to obtain an average illuminance of 50 lux on a 4m × 3m rectangular
room?
2
4
5
6
11․ The range of visual spectrum is
300nm
- 1000nm.
480nm
- 1000nm.
480nm
- 760nm.
300nm
- 760nm.
12․ Which lamp has a negative Colour Rendering Index (CRI)?
LED
Fluorescent
High
pressure sodium vapour
Low
pressure sodium vapour
13․ A 1000 W bulb fitted with a reflector illuminates an area of
3 m x 3 m with an average illumination of 450 lux. If the bulb has and
efficiency of 9 lumens / watt the efficiency of the reflector is
70
%.
30
%.
20
%.
45
%.
14․ What will be the total flux emitted by a source of 60 candle
power?
754.2
lumens.
0.001326
lumens.
60
lumens.
None
of these.
15․ From a uniform light source having luminous intensity of 300
candelas, there exists a plane surface 15 m below. The value of illuminance at
a point on the plane surface where the luminous flux rays are inclined at an
angle of 30 to the surface is
1.53
lux.
1.15
lux.
58.45
Kilolux.
17.32
lux.
16․ The solid angle subtended by an area of 2400 cm2 on
the surface of a sphere of diameter 1.2 m is
3
/ 2.
1
/ 3.
2
/ 3.
2
/ 5.
17․ In illumination technology total lumens emitted by source /
total lumens available after waste of light is equal to
waste
light factor.
utilization
factor.
beam
factor.
absorption
factor.
18․ The illumination at a point 5 meters below a lamp in 6 lux.
The candle power of the lamp is
30
140.
150.
200.
19․ Which among the following lamps has the maximum burning
hours?
LED.
Incandescent.
Metal
halide.
Compact
Fluorescent.
20․ A 200 candle power lamp is hung 4 m above the centre of
circular area of 5 m diameter. The illumination at centre of the area is
13.5
lux.
12.5
lux.
17.5
lux.
18.5
lux.
21․ Illumination can be
expressed in
radians.
lux.
lumens.
candela.
22․ Luminous efficacy of
a typical HPSV lamp is in between
40
- 70 lm/watt.
70
- 120 lm/watt.
120
- 200 lm/watt.
10
- 40 lm/watt
23․ Total flux or lumens
required in any lighting scheme depends inversely on
utilization
factor.
reduction
factor.
reflection
factor.
none
of the above.
24․ Wave length for red
colour is around
400
nm.
500
nm.
600
nm.
700
nm.
25․ Unit of luminous flux
is
lux.
steradians.
candela.
lumens.
26․ Which of the
following statement is correct?
Light
consists of electromagnetic waves.
Light
consists of ultraviolet waves.
Light
consists of infrared waves.
Light
consists of gamma rays.
27․ Luminous efficiency
of a fluorescence lamp is
70
lumens / watt.
60
lumens / watt.
40
lumens / watt.
30
lumens / watt.
28․ The illumination of
the surface varies directly with cosine of the angle between normal to surface
and direction of the inclined light is given by
law
of square inverse.
Lambert’s
cosine law.
both
A and B.
none
of the above.
29․
___________________________ factor is defined as the ratio of the illumination
when everything is clean to illumination under normal working conditions.
Depreciation.
Maintenance.
Utilization.
Absorption
factor.
30․ The work of ballast
in a fluorescent tube is to
limit
the flow of current.
provide
a kick start when voltage is induced.
both
‘a’ and ‘b’.
None
of these.
Answers ILLUMINATION
