Question

Q16.(a) Write joules law of heating

(b) two lamps one rated 100 watt 2​

Answer 1

╚═══❖•ೋ° ANSWER °ೋ•❖═══╝

(A) ♨♨ JOULES LAW OF HEATING:- ♨♨

• The amount of heat produced in a conductor due to the flow of electric current through it is directly proportional to the resistance offered by the conductor when the time of flow and the magnitude of the current is constant.

(B) From Joule's Law of heating,

P=V²/R

For first lamp,

R¹ =220²/100

For second lamp,

R²=220²/60

When they are connected in parallel,

1/Req= 1/R¹+ 1/R²

==> 1/220²/100+ 2/220²/60

==> Req =220²/160

From Ohm's Law,

V=IReq

220= 220²/160 ×I ( current)

I=0.73 A. ( Amphere)