The luminous efficiency of a sodium vapour lamp is:a)40-50 lumens/Wb)5...
Ratings of normal sodium vapour lamp:
1) The efficiency of sodium vapour lamp is lies between 40 and 50 lumens/W
2) Normally these lamps are manufactured in 45 W, 60 W, 85 W and 140 W ratings
3) The normal operating temperatures of these lamps are 300° C
4) The average value life of the sodium vapour lamp is 3000 hr and these are not affected by voltage variations
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The luminous efficiency of a sodium vapour lamp is:a)40-50 lumens/Wb)5...
Luminous Efficiency of Sodium Vapour Lamp
Luminous efficiency is the ratio of the luminous flux emitted by a light source to the power consumed by the source. Sodium vapour lamps are a type of high-intensity discharge (HID) lamps that produce light by the excitation of sodium vapour.
The luminous efficiency of a sodium vapour lamp is given as:
a) 40-50 lumens/W
This means that for every watt of power consumed by the lamp, it produces around 40-50 lumens of light.
Factors Affecting Luminous Efficiency
The luminous efficiency of a lamp depends on various factors such as:
1. Lamp Type: Different types of lamps have different luminous efficiencies. For example, LED lamps have higher luminous efficiencies than incandescent lamps.
2. Lamp Design: The design of the lamp also affects its luminous efficiency. For example, lamps with better reflectors or lenses can direct more light towards the desired area, resulting in higher luminous efficiency.
3. Operating Conditions: The operating conditions of the lamp, such as the temperature and voltage, can affect its luminous efficiency. In general, lamps operate at their maximum efficiency when they are operated at their rated voltage and temperature.
Advantages of Sodium Vapour Lamps
Sodium vapour lamps have several advantages over other types of lamps, such as:
1. Energy Efficiency: Sodium vapour lamps are more energy-efficient than incandescent lamps and some other types of HID lamps.
2. Long Life: Sodium vapour lamps have a longer lifespan compared to other types of lamps.
3. High Luminous Efficacy: Sodium vapour lamps have a high luminous efficacy, meaning they produce more light per watt of power consumed.
4. Good Color Rendering: Sodium vapour lamps have good color rendering properties, making them suitable for outdoor lighting applications.
Conclusion
The luminous efficiency of a sodium vapour lamp is around 40-50 lumens per watt. This makes them an energy-efficient lighting option with a long lifespan and good color rendering properties.
The luminous efficiency of a sodium vapour lamp is:a)40-50 lumens/Wb)5...
The efficiency of a sodium vapour lamp under practical conditions is about 40-50 lumens/watt. Such lamps are manufactured in 45, 60, 85 and 140 W ratings. The average life is about 3000 hours and is not affected by voltage variations
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