Question

Ajit had a high-tension tower erected on his farmland. He kept complaining to the authorities to remove it as it was occupying a large portion of his land. His uncle, who was a teacher, explained to him the need for erecting these towers for efficient transmission of power. As Ajit realized its significance, he stopped complaining.
Answer the following questions:
(a) Why is it necessary to transport power at high voltage?
(b) A low power factor implies large power loss. Explain.
(c) Write two values each displayed by Ajit and his uncle.

Answer 1

Hint: To solve this question, we need to know the basic theory related to the power factor. As we know power factor is basically the how efficiently source current is converted into the load current. Here we will use some basic relations or formulas to establish given conditions as discussed below.

Complete step by step answer:
(a) If high voltage is used to transmit power,
then the current through the wire will be less as I = $\dfrac{P}{V}$.
 Hence, the power loss = ${I^2}R$ will also be less.

(b) The power is given as P=VI $\cos \phi $, where $\cos \phi $ is the power factor.
To supply a given power at a given voltage of transmission.
if $\cos \phi $ is small, then according to the above equation, current I has to be large. This leads to a large power loss caused by heat which is given as H = ${I^2}R$.
 Hence, a low power factor implies large power loss.

(c) Values displayed by Ajit:
Understanding nature and being proactive.
Values displayed by uncle: Patience and intelligence

Note:
Always remember that In AC circuits, the power factor is the ratio of the real power that is used to do work and the apparent power that is supplied to the circuit.
The power factor can get values in the range from 0 to 1.
When all the power is reactive power with no real power (usually inductive load) - the power factor is 0.