AC power is transmitted from a power house at a high voltage because

The correct answer is Option (2) → it is more economical due to less power loss

Option (1) the rate of transmission is faster at high voltages — Incorrect. The voltage does not change how fast electrical energy travels along the line. It changes only the current needed to carry a given power.

Option (2) it is more economical due to less power loss — Correct. For a given power \( P=VI \), a higher voltage means a smaller current, so the heat loss \( I^{2}R \) in the long line wires is cut down. The voltage is stepped up by a transformer at the power house and stepped down again near the consumers.

Option (3) power cannot be transmitted at low voltages — Incorrect. Power can be sent at a low voltage, as the 240 V supply in our homes shows. Over long distances, the larger current would waste far more energy as heat.

Option (4) it is a precaution against theft of transmission lines — Incorrect. The high voltage is chosen to reduce the energy lost as heat in the lines. It has nothing to do with protecting the wires.

NCERT (2026-27):
Transformers – “The large scale transmission and distribution of electrical energy over long distances is done with the use of transformers. The voltage output of the generator is stepped-up (so that current is reduced and consequently, the I²R loss is cut down).”