Question

Power is transmitted from a powerhouse on high voltage AC because

• A. the rate of transmission is faster at high voltage.
• B. it is more economical due to less power loss.
• C. the life of current carrying wire is prolonged.
• D. of a precaution against theft of transmission line.

Answer 1

The correct option is B it is more economical due to less power loss.

power wasted as heat is $V^2/R$ or $I^{2}R$. In long distance transmission of electricity ,long wires are used which have very high resistance , $R\propto l$, so direct multiplication of $R$ into a high number will increase Power wasted ,so current should be low ,voltage can be high because resistance is denominator so it will reduce the power wasted as heat.So less power is wasted therefore it is more economical way.