Question

two lamps rated at 100w 220v and other at 40w 220v are conne6to a parallel 220v main supply calculate the current drawn from the supplier​

Answer 1

Answer:

 0.63 A

Explanation:

P1 = 100 W

So, $V_1^2$/$R_1$ = 100

or $R_1$ = $(220)^2$/100 = 484 ohm

P2 = 40 W

So, $V_2^2$/$R_2$ = 40

or $R_2$ =  $(220)^2$/40 = 1210 ohm

Equivalent Resistance when  $R_1$ and  $R_2$ are connected in parallel (Rp) =

 $R_1$ $R_2$/$R_1$ +  $R_2$ = 345. 7 ohm

Now, V = 220V

So, IRp = 220

So, I = 220/Rp= 220/345.7 = 0.63 A

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