Lamp efficiency is measured in ________

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SSC JE EE Previous Year Paper 14 (Held On: 26 Sep 2019 Morning)
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  1. lumen/watt
  2. lumen/lux
  3. candela/watt
  4. lux/watt

Answer (Detailed Solution Below)

Option 1 : lumen/watt
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Luminous efficiency: It is also known as radiant efficiency. It is defined as the ratio of energy radiated in the form of light, produces sensation of vision to the total energy radiated out by the luminous body.

Radiant efficiency = energy radiated in the form of light / total energy radiated by the body

Lamp efficiency is measured in lumen/watt.

Important Points:

Lamp

Lamp efficiency

Carbon filament lamp

3 – 4.5 lumen/watt

Osmium filament lamp

5 lumen/watt

Tantalum filament lamp

2 lumen/watt

Tungsten filament lamp

18 lumen/watt

Carbon arc lamp

9-12 lumen/watt

Flame arc lamp

8 lumen/watt

Neon discharge lamp

15 – 40 lumen/watt

Sodium vapour lamp(low pressure)

101-175 lumen/watt

Sodium vapour lamp(high pressure) 67- 121 lumen/watt

Mercury vapour lamp

30 – 40 lumen/watt

Fluorescent lamp

50 – 60 lumen/watt

Incandescent lamp

8 – 40 lumen/watt

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