Question

Three equal resistors connected in series with a battery, togrther dissipate 10W of power. What will be the power dissipated is the same resistances are connected in parallel across the same battery?

Answer 1

we know that

P = V²/R

so,

in series

P1 = V²/3R = 90

or

V² = 180R

and

for parallel, the equivalent resistance would be R/3

so,

P2 = V²/(R/3)

thus,

P1/P2 = (V²/3R) / (3V²/R)

so,

P2 = 9*P1 = 90W