An electricity-generating station needs to deliver 20 MW of power to a city 1.0 km away. A common voltage for commercial power generators is 22 kV, but a step-up transformer is used to boost the voltage to 230 kV before transmission.
(a) If the resistance of the wires is 2.0 ohms and the electricity costs about 10 cents/kWh, estimate what it costs the utility company to send the power to the city for one day?

Explanation:

Power to be transferred = 20 x 10⁶ W .

Voltage at which power is transferred V = 230 x 10³ V .

If current in the carrying wire is I

V x I = Power

230 x 10³ x I = 20 x 10⁶

I = 86.9565 A

Power loss in the transmission line

I² R , I is current and R is resistance

= 86.9565² x 2

= 15122.86 W

= 15.123 KW

In one day power loss

= 15.123 x 24 kWH .

= 363 kWH .

Cost = 363 x 10

= 3630 cent

= 36.30 dollar .

explanation:

earth's surface is mainly heated by the absorption of infrared radiation from the sun.

evaporation occurs because molecules in liquid water are warmed ( usually by the sun) and vibrate quicker, becoming less dense and rise.

condensation occurs because molecules in water vapor are cooled and therefore vibrate more slowly thus becoming more dense and eventually fall to earth.

lines of equal barometric pressure on a weather map are called: isobars : lines of equal temp on a weather map are called: isotherms.​