The incandescent lightbulb was actually invented by Humphry Davy in 1802. It was not commercializable in that form. Joseph Swan was successful in making a commercializable unit in the late 1870s. He may have been granted the first light bulb patent (British patent 4933, issued in 1880). Thomas Edison was also developing electric lighting at that time. He applied for US patents as early as 1878 So why is Edison credited as the inventor? Partly because he was the first to design and manufacture a robust lighting system having a bulb with an effective incandescent material, higher vacuum inside the bulb, and high resistance so power distribution from a central source was possible. Perhaps more importantly was the development ofsupply sources and materials for distribution networks. A modem incandescent lightbulb is shown below. Overall efficiency, defined as light power out divided by electrical power in, is about 2.5% for a 100 W unit. 1 1. outline of glass bulb 2. Low pressure inert gas (argon, nitrogen, krypton, xenon) 3. Tun ten filament 5) 4. Contact wire (goes out of stem) 5. Contact wire (goes into stem) 6. Support wires (one end embedded in stem; conduct no current) 7. Stem (glass mount) 8. Contact wire (goes out of Identify five different systems that could be used for an energy analysis (some combination Draw arrows for each systems\' energy flow process(es)-W Qooeduction, Qconvection, radiation. Solution To conduction and convection of heat must have the medium. in vaccum only radiation is there. given problem the heat coming out from the tungsten filament(3). the work supplied by the electrical current through the wires. first humphry davy invented incandescent bulb having vaccum inside so there is no possibilty of heat transfer through conduction or convection. next edison filled with the low pressure inert gases. beacuse of that from hot Tungsten filamet to inert gases heat transfer occurs through convection. next inertgasses to glass or stem heated by the convection (fluid and solid interaction) again glass to sourroundings is convection(solid and fluid interaction) radiation is always there beacuse it possible with medium and with out medium contact wires are heated up through the conduction..

1. The incandescent lightbulb was actually invented by Humphry Davy in 1802. It was not
commercializable in that form. Joseph Swan was successful in making a commercializable unit
in the late 1870s. He may have been granted the first light bulb patent (British patent 4933,
issued in 1880). Thomas Edison was also developing electric lighting at that time. He applied for
US patents as early as 1878 So why is Edison credited as the inventor? Partly because he was the
first to design and manufacture a robust lighting system having a bulb with an effective
incandescent material, higher vacuum inside the bulb, and high resistance so power distribution
from a central source was possible. Perhaps more importantly was the development ofsupply
sources and materials for distribution networks. A modem incandescent lightbulb is shown
below. Overall efficiency, defined as light power out divided by electrical power in, is about
2.5% for a 100 W unit. 1 1. outline of glass bulb 2. Low pressure inert gas (argon, nitrogen,
krypton, xenon) 3. Tun ten filament 5) 4. Contact wire (goes out of stem) 5. Contact wire (goes
into stem) 6. Support wires (one end embedded in stem; conduct no current) 7. Stem (glass
mount) 8. Contact wire (goes out of Identify five different systems that could be used for an
energy analysis (some combination Draw arrows for each systems' energy flow process(es)-W
Qooeduction, Qconvection, radiation.
Solution
To conduction and convection of heat must have the medium.
in vaccum only radiation is there.
given problem the heat coming out from the tungsten filament(3).
the work supplied by the electrical current through the wires.
first humphry davy invented incandescent bulb having vaccum inside so there is no possibilty of
heat transfer through conduction or convection.
next edison filled with the low pressure inert gases. beacuse of that from hot Tungsten filamet to
inert gases heat transfer occurs through convection.
next inertgasses to glass or stem heated by the convection (fluid and solid interaction)
again glass to sourroundings is convection(solid and fluid interaction)
radiation is always there beacuse it possible with medium and with out medium
contact wires are heated up through the conduction.