Question

An electric bulb is rated as 25 watt-250 volt. How much
current will flow through it on connecting it with 250 volt
mains supply and how much its resistance will be ?​

Answer 1

Generally electrical appliances such as an electric bulb, geyser, heater, etc. are rated with power and voltage. If a bulb is rated 100W - 250V, it means that when a bulb is lit on a 250V supply, it consumes 100 W of electric power. This means that, 100 Joules of electrical energy gets converted into heat and light energy in 1 second.
From this rating we can calculate the resistance of the filament of the appliance while it is glowing and also the current which flows through it.
SinceP=
R
V
2

​
,R=
P
V
2

​
.
For the bulb rated as 100 W - 250 V, the resistance of its filament
R=
P
V
2

​
=
100
250
2

​
=625Ω.
The resistance of the filament of a bulb is much less than this value when it is not lit because the resistance of a filament increases with the increasing temperature.
Hope it helps you

Answer 2

Answer:

hope i t will help you

and thanks