Question

2 bulbs have filament of same length. if one is 40 watt and other 60 watt,which has thicker filament?

Answer 1

Answer:

generally, an electric Appliance such as electric bulb.,geyser,heater etc. is rated with power and voltage. for example, an electric bulb is rated as 100W -220V.it means that if the bulb is lighted on a 220V supply ,it consumes 100W electrical power (I. e. 100 J of electrical energy is consumed by the bulb in 1 s or in other words, 100 J of electrical energy is converted in the filament of bulb into light and heat energy in 1 second).

Explanation:

from the power rating of an appliance, we can find the safe limit of current which can flow through that appliance.

from relation P=VI .

safe limit of current for an appliance

I=power of appliance

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voltage at which it works

for example, for a bulb rated 100W, 220 V, the safe limit of current when it is lighted at 220V is

I=P =100W =0.45A

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V. 220V

the table below gives the power rating of some common appliances.