two electric bulbs have 40w and 60 w rating at 220 v . then ratio of their resistances will be?

Question

plz give me a detailed explanation in written .

thank you

Answer 1

Hi, you have to apply Ohm`s law

U = R*I where U in V equals the voltage
I in A the current and
R in Ohm the resistance.

The power in a electrical circuit is

N = U*I = U^2/R in W

Example: N1 = 40W; N2 = 60 W

The ratio N1/N2 = R2/R1 = 40/60 = 2/3

Answer 2

For the 40W bulb:
V=220v
P=40W
Now, R1=v2/p
there fore R1=220*220/40 ohm

For the 40W bulb:
V=220v
P=60W
Now, R2=v2/p
there fore R2=220*220/60 ohm

So the Ratio will be
R1:R2=6:4 means 3:2

Answer 3

P = E²/R so
40 = 220²/R1 (where R1 is 40W bulb) and
60 = 220²/R2 (where R2 is 60W bulb) so that
40/60 = (220²/R1)/(220²/R2) = R2/R1 and
(2/3)*R1 = R2

Doug

Answer 4

p=v^2/R
P1/P2=R2/R1
s o R2/R1=40/60=2/3