Question

(A) Name the transformer used in the power transmitting station of a power plant.
(B) What type of current is transmitted from the power station?
(C) At what voltage is this current available to our household?

Answer 1

Hint:
In the power transmitting station of a power plant the voltage is increased and the current is decreased keeping power equal. So a step up transformer is used. The alternating current is transmitted from there and then it is made to go through the step down transformer and reaches our house at $220V$.

Complete step by step answer:
After the electricity is generated in the generating station, it has to travel large distances from the stations to the various areas for supply. Now high current will cause a high heating effect which will melt the wires and cause very high resistive loss. So this current is transferred through a step up transformer to increase the voltage and decrease the current keeping the power constant. The high voltage transmission is more efficient because it allows transmitting a larger portion of the generated power to the substations which also translates to operational cost savings.
Hence in the power transmitting station of the power plant, a step up transformer is used.
The type of current that is transmitted from the power station is the alternating current which is also known as the ac current.
From the generating stations, after the current is passed through the step up transformer, then the current at the high voltage reaches the substations, there the current is passed through the step down transformer where the voltage is reduced to an amount of $220V$ which is supplied to the household.
So the voltage at which the current is available to our household is $220V$.

Note:
The transformer in which the output voltage is greater than the input voltage is called a step up transformer. It decreases the current in the output by keeping the power in the input and output the same. As the power loss in the transmission line is directly proportional to the square of the current, so by decreasing the current the power loss decreases.