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He found that a metal rod from the top to the bottom of a building makes the flow of lightning harmlessly pass through.

Choke coil works as an inductor and creates high voltage needed for ionization of gases in the tube. For the tubelight to glow, gases present in the tube should be ionized which requires high voltage, but the supply at domestic level is only around 220 V. The starter switches on and off the current through choke coil, which helps to build high transient voltage around choke coil.

Live wire is the wire with red covering.

Rectifiers are circuits made of diodes and are used to convert AC to DC. 

Rubber, wood, glass and porcelain are the best insulators.

Dry air is an insulator.

Nitrogen is filled in bulbs. Argon is another noble gas and is used to keep light bulb filaments from burning away. Since argon is non-reactive, it is filled in a light bulb instead of regular air, which contains oxygen that can cause a burning reaction when exposed to the thin metal filaments found in light bulbs. Other noble gases include krypton, xenon and radon.

 A bird sitting on a high power line is not affected practically as there is no short circuit.