Three resistors of equal resistances when connected in series across a voltage souce , dissipate 100 watt of power. What would be the power dissipated . If the resistors are connected in parallel across the same source of emf?

Explanation

If each resistance be r , then the equivalent resistance in series , `R_(1)=3r` , and the equivalent resistance in parallel , `R_(2)=(r)/(3)`.
In both the combinations , potential differnce across the two ends is equal to V (say ).
`therefore` In case of series combination , power , `p_(1)=(V^(2))/(R_(1))` and in case ofparallel combination ,power , `P_(2)=(V^(2))/(R^(2))` .
`therefore" " (P_(1))/(P_(2))" or , "P_(2)=P_(1).(R_(1))/(R_(2))=100xx(3r)/(r/3)=900W`