Roys 'Illuminating' Quiz: Electric Lighting
We hope that you will find this brief quiz both entertaining
and educational.
Question A
You have accidentally bumped your antique incandescent desk
lamp, and are plunged into darkness. You travel to your local
electrical store. Should you ask for a replacement bulb or
a replacement lamp? Why?
Question B
Can you name the two inventors from different countries who
are credited with the invention of incandescent electric lighting,
and the relevant year?
Question C
A large electrical manufacturer of lighting equipment had
a SLOGAN and TRADEMARK, which read as follows:
O for an...
Osram.
Can you explain how the Trademark (Osram) was derived?
Question D
The illumination efficiency of electrical light sources is
defined by the units; Lumens/watt.
Do you know the relative efficiency values for the following:
- Lamps of Question B
- Commercial Incandescent Lamps of up to 100 watts
- Tubular Fluorescent Lamps of 40 watts
Solutions & Answers
Answer A
It is preferable and more correct to use the word 'lamp'.
The word 'bulb' derives from a Greek botanical term 'bolbos',
which is relevant to a geometric shape, and not to the function
of an item. Bulb is descriptive of the spherical outer glass
envelope of an incandescent lamp, but does not include the
complete assembly of filament, cap, etc.
Answer B
Joseph Swan, England, 1879/80. He used carbon filament of
parchmentised cotton, (prior treatment with sulphuric acid).
Founded the Swan Electric Light Company in Feb 1881.
Thomas Edison, America,
1879/80. He used a filament of carbonised bamboo to provided
structural strength. The date of his first successful lamp
was cited as October 1879, and he founded the Edison Electric
Light Company in March 1882.
The respective companies merged in October 1883 to form the
Edison & Swan United Electric Light Company Ltd.
Answer C
OS from the element Osmium. RAM from Wolfram, the ore from
which tungsten is obtained.
Osmium is the metallic element having the highest density
of 22.6 gm/cm3, and is one of the densest materials known.
It's melting point is in excess of 3000°C. Osmium is of
limited availability in nature (0.0004 p.p. million in the
earth's crust). It was introduced to lamp filament production
in Germany around 1899.
Wolfram (iron manganese tungstate) is the ore from which
tungsten is refined. Tungsten has a density of 19.3gm/cm3,
and a melting point in excess of 3300°C, which is the
highest melting point of all the metals. The first tungsten
filament lamp was produced in 1907; and the OSRAM Tungsten
filament lap was marketed from 1919.
Answer D
Lamp efficiency of:
- Edison and Swan's lamps is 3 to 5 lumens/watt.
- Commercial Incandescent lamps - 9 to 13 lumens/watt.
- Tubular Fluorescent lamps (40 w) - 50 to 75 lumens/watt.
HOW DID YOU SCORE!?
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