Question

the electric power consumed by a device may be calculated by using either of the two expressions p = i square r or P = V square by R the first expression indicates that it is directly proportional to R while II indicates that it is inversely proportional to R how can the dependence of P on r be explained

Answer 1

1-In case of



,

 if I is constant with R.and in case of

, P is inversely proportional to R if V is constant with R.

2- For series combination of the resistors,current will be same.

Electric power consumed by the resistance R,=P1=

Electric power consumed by the resistance 2R=P2=

Now,dividing P1 by P2,we get

 P1/P2=1/2