Question

An electric bulb rated at 80 W, 240 V has inside it a heating filament. Each
end of the filament is connected to a supporting straight wire of diameter
1.0 mm and length 4.0 cm. When the bulb is switched on and functioning
at the given rating, the filament temperature is 1000°C. The temperature at
the other end of each supporting wire is 60°C. Estimate the ratio of power
loss due to thermal conduction of heat away from the filament along the two
supporting wire to the power supplied to the filament
(Thermal conductivity of the material of supporting wire = 59 W m-1 K-?)​

Answer 1

Answer:

A filament bulb

is to be used in a

main supply. When a resistance

is connected in series, it works perfectly and the bulb consumers

. The value of

is