Question

The equal resistors connected in series across a source of emf together dissipate 5W of power. Of the same resistors are connected in parallel across the same source of emf , the power dissipated will be?

Answer 1

I assume question is 'Two equal resistors ' and not 'The equal resistors'.

Now, keep in mind, power is always additive, as it is propotional to both V and I
P= VI
Resistance, R = V/I, that means it is propotional to V, but inversely proportional to I.

But as P is directly proportional to both V and I, it is always additive., no matter in series or paralle.

So, in parallel, you get same power as in series, that is 5W.