# Sources of Light 3

Questions Electrician and Wireman: Sources of Light 3

Subject: Sources of Light 3

Part 3: Objective questions and answers of Sources of Light

Q1. A lamp has a total luminous flux of 1570 lumens. Its mean spherical candle power is

a) 1570

b) 500

c) 250

d) 125

Q2. Glare is caused due to

a) Excessive luminance

b) Excessive lighting contrast in the field of vision

c) Either a or b

d) None of the above

Q3. Which of the following colour has wave length between blue and yellow?

a) Violet

b) Orange

c) Red

d) Green

Q4. Energy radiated continuously in the form of light-waves is called :

a) Luminous-flux

b) Luminous-intensity

c) Lumen

d) Illumination

Q5. The metric unit of illuminance (or) illumination is:

a) Lux

b) Lumen

c) Candela

d) Lumens/watt

Q6. The illumination of a surface is :

a) Directly proportional to its distance from the source

b) Inversely proportional to its distance from the source

c) Directly proportional to the square of its distance from the source

d) Inversely proportional to the square of the distance from the source

Q7. The illumination required for a workplace where fine work is performed will be in the order of…….

a) 1000 lumens/ Meter

b) 1000 lumens/sq. Meter

c) 1500 lumens/sq. Meter

d) 2000 lumens/sq. Meter

Q8. What is the working temperature of filament lamp?

Q9. What is the main advantage of coiled coil lamp?

a) High melting point

b) Higher light output

c) Low operating voltage

d) Low power consumption

Q10. What is the unit of luminous efficiency?

a) Lux

b) Lumen

c) Lumen/m

d) Lumen/watt

Q11. What is the term refers luminous flux given by light source per unit solid angle?

a) Lumen

b) Candela

c) Illuminance

d) Luminous intensity

Q12. What is the function of leak transformer in high pressure sodium vapour lamp circuit?

a) Reduce the starting current

b) Reduce the working voltage

c) Increase the working voltage

d) Ignite the high voltage initially

Q13. Which term refers that the flow of light into a plane surface?

a) Lumen

b) Illuminance

c) Luminous flux

d) Luminous intensity

Q14. Which type of light fitting design has free from glare?

a) Semi direct type

b) Semi indirect type

c) Direct lighting type

d) Indirect lighting type

Q15. Which type of lighting system is used for flood and industrial lighting?

a) Direct lighting

b) Indirect lighting

c) Semi-direct lighting

d) Semi-indirect lighting

Q16. The illumination required for a workplace where fine work is performed will be in the order of :

a) 500 lumens/sq. Meter

b) 1000 lumens/sq. Meter

c) 1500 lumens/sq. Meter

d) 2000 lumens/sq. Meter

Q17. The illumination required for a workplace where rough or unskilled work is performed will be in the order Of…….

a) 100 lumens/sq. Meter

b) 150 lumens/sq. Meter

c) 200 lumens/sq. Meter

d) 250 lumens/sq. Meter

Q18. What is the SI unit of luminous intensity?

a) Lux

b) Lumen

c) Candela

Q19. Which material is coated in tungsten electrode of a fluorescent tube lamp?

a) Silver oxide

b) Phosphor powder

c) Fluorescent powder

d) Barium and stroatium oxide

Q20. In a high pressure mercury lamp, to vaporize all the mercury and for the lamp to reach full brilliance, it requires:

a) 2 to 4 minutes

b) 4 to 6 minutes

c) 6 to 8 minutes

d) 8 to 10 minutes

Part 3: Objective questions and answers of Sources of Light