ONLINE MCQ EE-ILLUMINATION 7

ONLINE MCQ EE-ILLUMINATION 7

Q61. A mercury vapour lamp gives ____ light.

A.  white
B.  pink
C.  yellow
D.  greenish blue

Ans. D

Q62. In an incandescent lamp bird cage filament is usually used in vacuum bulb so as to

A.  reduce the oxidation phenomenon
B.  reduce the convection losses
C.  have uniform radiations
D.  increase the life span of the filament

Ans. C

Q63. Soft shadows are produced by

A.  using surface source of light instead of point source of light
B.  increasing the number of lamps
C.  both (a) and (b)
D.  none of the above

Ans. C

ONLINE MCQ EE-ILLUMINATION 7

Q64. Fine diameter tungsten wires are made by

A.  turning
B.  swaging
C.  compressing
D.  wire drawing

Ans. D

Q65. On which of the following factors does the depreciation or maintenance factor depend ?

A.  Lamp cleaning schedule
B.  Ageing of the lamp
C.  Type of work carried out at the premises
D.  All of above

Ans. D

Q66. Due to moonlight, illumination is nearly

A.  3000 lumens/m2
B.  300 lumens/m2
C.   30 lumens/m2
D.  0.3 lumen/m2

Ans. D

ONLINE MCQ EE-ILLUMINATION 7

Q67. In electric discharge lamps for stabilizing the arc

A.  a reactive choke is connected in series with the supply
B.  a condenser is connected in series to the supply
C.  a condenser is connected in parallel to the supply
D.  a variable resistor is connected in the circuit

Ans. A

Q68. Sometimes the wheels of rotating machi­nery, under the influence of fluorescent lamps appear to be stationary. This is due to the

A.  low power factor
B.  stroboscopic effect
C.  fluctuations
D.  luminescence effect

Ans. A

Q69. Stroboscopic effect due to use of discharge lamps in workshops results in moving machinery appearing

A.  stationary
B.  stationary running slow
C.  stationary running in reverse direc­tion
D.  all of the above

Ans. D

ONLINE MCQ EE-ILLUMINATION 7

Q70. Reflectors are provided with slits at the top to

A.  introduce chimney effect for clean­ing
B.  reduce colour contrast
C.  reduce heating effect
D.  do all of the above functions

Ans. D