Question

2 bulbs whose resistences arew in the ratio 1:2 are connected in parallel to a source of constant voltage . what will be ratio of power dissipation of these ?

Answer 1

Explanation:

2 bulbs whose resistences arew in the ratio 1:2 are connected in parallel to a source of constant voltage . what will be ratio of power dissipation of these ?

Answer 2

Answer: 2:1

Explanation:

Let the resistances of the two bulbs be R and 2R.

And their constant voltage of the source be V.

Then,

Power dissipated by the 1st bulb is

P1 = V×I1

P1 = V×V/R ( From Ohm's law I = V/R)

P1 = V²/R

Power dissipated by 2nd bulb is

P2 = V×I2

P2 = V×V/2R

P2 = V²/2R

Now, the ratio of power dissipation by these = V²/R / V²/2R

= V2/R × 2R/V²

= 1/R × 2R

= 2 : 1