Why is electric power transmitted at very high voltage over long distances to reduce Ohmic loss?

$5.0 \, A$ current is set up in an external circuit by a $6.0 \, V$ storage battery for $6.0 \, \text{minutes}$. The chemical energy of the battery is reduced by:

Water in an electric kettle starts boiling in $15 \ min$ after being switched on. If the length of the heating wire is reduced to $2/3$ of its original length,the time taken to boil the same amount of water will be ........... $min$.

How many calories of heat will be produced approximately in a $210\, W$ electric bulb in $5$ minutes?

$A$ $220\, V$,$1000\, W$ bulb is connected across a $110\, V$ mains supply. The power consumed will be ............ $W$.

Four wires of the same diameter are connected in turn between two points,maintained at a constant potential difference. Their resistivities and lengths are: $\rho$ and $L$ (wire $1$),$1.2\rho$ and $1.2L$ (wire $2$),$0.9\rho$ and $0.9L$ (wire $3$),and $\rho$ and $1.5L$ (wire $4$). Rank the wires according to the rates at which energy is dissipated as heat,greatest first.