Question

a torch bulb has a resistance of 1ohm when cold it draws a current of 0.2a from a source of 2v and glows calculate 1>the resistance of the bulb when glowing and 2>explain the reasons for the different in resistance

Answer 1

i) When the bulb glows:

V = I R —- Ohm’s law R = V/I = 2/.2 =10 Ω

(ii) Resistance of the filament of the bulb increases with increase in temperature. Hence when it glows its resistances is greater than when it is cold.

Hope this helps u!!

Answer 2

i) When the bulb glows:

V = I R —- Ohm’s law R = V/I = 2/.2 =10 Ω

(ii) Resistance of the filament of the bulb increases with increase in temperature. Hence when it glows its resistances is greater than when it is cold.

Hope this helps u!!