Question

What will be current drawn drawn by a lamp load at 270V,40 watts connected to 230V supply?
(Note : first find resistance for 270V,40W bulb, then find current for 230V)​

Answer 1

Explanation:

First find out the resistance

we know P = V²/r

=> r = V²/P

= 250²/40

= 1562.5 Ω.

2. Now Current

We know V=IR

=>I = V/R

= 230/1562.5

= 147.2 mA.

Hope this will help.