Tuesday, December 25, 2018

MCQ's ON ILLUMINATION




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.
                            CLICK  HERE FOR ANSWER KEY

Answers  ILLUMINATION


1

2

3

4

5

6

7

8

9

10

B

C

C

B

B

D

C

B

A

A

11

12

13

14

15

16

17

18

19

20

C

D

D

A

B

C

A

C

A

B

21

22

23

24

25

26

27

28

29

30

B

B

A

D

D

A

C

B

A

C


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