Question

A small bulb has a resistance of 2 when cold. It takes up a current of 0.4 a from a source of 4v and then starts glowing. Calculate (i) the resistance of the bulb when it is glowing and (ii) elaborate on the reason for the difference in resistance?

Answer 1

Answer:

(i) R =10ohm

(ii) resistance increases with heat...

Explanation:

(i) V=IR

R=V/I

R=0.4/4

R=10ohm.....

(ii) H=I^2 Rt

H is directly proportional to R

this means that resistance increases with heat of bulb ...