What determines the rate at which energy is delivered by a current?

How can three resistors of resistances $2\, \Omega$,$3\, \Omega$,and $6\, \Omega$ be connected to give a total resistance of $1\, \Omega$?

Judge the equivalent resistance when the following are connected in parallel: $1 \, \Omega$,$10^3 \, \Omega$,and $10^6 \, \Omega$.

$A$ copper wire has a diameter of $0.5\, mm$ and a resistivity of $1.6 \times 10^{-8}\, \Omega \, m$. What will be the length of this wire to make its resistance $10\, \Omega$? How much does the resistance change if the diameter is doubled?

An electric heater of resistance $8 \, \Omega$ draws $15 \, A$ from the service mains for $2$ hours. Calculate the rate at which heat is developed in the heater (in $W$).

Will current flow more easily through a thick wire or a thin wire of the same material,when connected to the same source? Why?