2. lumen efficiency of vaccum filament lamp 10 lumen /watt to 14 lumen /watt.
3. Melting point of Osmium and tantalum filaments is 2700°C to 2900°C.
4. Melting point of Tungsten 2400°C to 2750°C .
5. Gas filled coil filament lamp efficiency around 10 to 25 lumen /watt.
6. Gas filled coil filament lamp Argon (85%) and Nitrogen (15%) .
7. Normal life of gas filled coil filaments is 1000 hours.
8. Advantage of gas filled coil filament lamp is works at unity power factor.
9. Na vapour lamp and Hg vapour lamp is a Gaseous discharge lamp .
10. Power factor of Na vapour Lamp is low .
11. Lamp efficiency of Na vapour Lamp is 40 to 50 lumen\ watt.
12. Lamp efficiency of Hg vapour Lamp is 40 lumen /watt and size 250 watt to 400watt.
13. Highest colour rendering obtained in incandescent/halogen Lamp 100 CRI.
14. There is no Flicker/stroboscopic effect on tungsten filament Lamp while in fluroscent tubes it contains.
15. Working hours of Fluroscent Tubes is 6000 hrs.
16. Lumen efficiency of CFL is 50 to 90 lumen/watt.
17. Life of CFL is 8000 working hrs .
18. Life of LED is 4000 working hrs .
19. Lumen efficiency of LED is 120 to 200 lumen\ watt.
20. In a direct Lighting scheme 90 to 95 percent Light falls downwards directly on the objects ,produce more glare and shadows by using deep reflectors.
21. Indirect lighting scheme 90 to 95 % light directed upwards by using diffusing reflectors.
22. In a semi direct lighting 60 % light is directed downwards and 40 % light is directed upwards ,less glare ,best suited for rooms with high ceiling.
23. In semi - indirect lighting 60 to 90 % of total light is thrown upward to the ceiling and rest reaches the working plane directly.
24. Art and drawing (lumen/m^2) is 400.
25. Staircase ,corridors ,waiting room (Lumen/ m^2) is 75 .
26. Normal office work and class room (Lumen/ m^2) is 250.
27. Fine work and watches (Lumen/m^2) is 1000.
28. Dielectric heating is used for sterilization.
29. Candle power = illumination× (Distance)^2.
30. If the distance from the source becomes half, effect on illumination will become 4 times( according to law of inverse square E proportional (1/d^2) ).
31. LED can emit 300 lumens/watt is more than fluroscent and incandescent.
32. LED lamps have the longest life expectancy (50,000 hours).
33. Illumination efficiency for :
1) Mercury vapor lamp - 35-65 lumens/watt
2) Incandescent lamp - 15-20 lumens/watt
3) Sodium vapor lamp - 200 lumens /watt
4) Fluorescent lamp - 70-90 lumens/watt
34. The illumination level in houses is in the range of 100-140 lumen/m2.
35. The method of speed control adopted in 25 kW, single-phase, 50 Hz traction is: Tap changing control of transformer.
36. Field test is usually conducted to determine the efficiency of traction motor this test is more reliable and efficiency for testing at traction system.
37. unit of luminance = Candela/m^2.
38. Spot welding is used to weld metal pieces whose thickness is less than 12 mm.
39. In percussion welding, the heat is produced by a rapid discharge of stored electrical energy.
40. Butt joint weld may be used on material up to 25 mm thick.
41. Soda acid extinguisher fire extinguisher in not suitable for electric fire.
42. Flood lighting are broad beamed, high intensity artificial lights and hence are used in various stadiums.
43. Sodium vapour lamp uses sodium in a state to produce light. They are among the most efficiency light source producing up to 200 lumen/W.
44. For the Arc heating, the electrodes are made up of graphite .
45. Resistance heating is based on I^2R effect and highly resistive in nature that’s why it has maximum pf.
46. Candle power = lumen /solid angle
47. lamp efficiency = luminous flux /input power
48. Electric fuse is made up of alloy of lead and tin and has low melting point.
49. The Seebeck effect is a phenomenon in which a temperature difference between two dissimilar electrical conductors or semiconductors produces a voltage difference between the two substances.