Question

Two bulbs are marked 100W ,220V and 60W, 110V.

Calculate the ratio of their resistance.

Answer 1

(1) P1=100 W

V1 = 220 V

________________

P = V×I

P = V × (V/R)

P = V^2/R

________________

100 = (220×220)/R1

R1 = 484 ohm

________________

(2) P2 = 60 W

V2= 220 V

________________

60 = (220×220)/R2

R2 = 806.6 ohm

_______________

Hence R2 is greater than R1

Answer 2

$<marquee behavior=move bgcolor= White > <h1> ☺️☺️HELLO✌️✌️ </h1></marquee>$

We know that R = V²/P

The resistance R1 =(220×220)/100 = 484 ohm

and R2:= (110/110)/60=1210/6=201.67 ohm.

Therefore, R1/R2= 484/1210×6=2.4

Thanks!