Question

5. An electrical power plant generates electricity with a current of 50 A and a potential difference of 20 000 V. In order to minimize the power losses due to the high current heating up the line, a transformer steps up the potential difference to 500 000 V before it is transmitted. What is the current in the transmission lines?

Answer 1

Answer: Current = 2 A

Explanation:

Given that an electrical power plant generates electricity with a

current I = 50 A

Potential difference V = 20 000 V

The resistance R will be achieved by Ohms law formula which state that

V = IR

But the power generated will be the product of potential difference and the current

Power P = IV

P = 50 × 20000

P = 1, 000000 W

When the transformer steps up the potential difference to 500 000 V before it is transmitted

Power is always constant.

Using the formula for power again with

V = 500000

1000000 = 500000× I

Make I the subject of formula

Current I = 1000000/500000

Current I = 2 A