Explain why a transformer is used in electrical power lines.
Power stations use step-down transformers to decrease the voltage of the electrical output. The power lines have a constant resistance (say, R Ohms) which means there is a power loss across the lines given by P = IV. By using Ohm's law (V = IR), we can obtain the formula P = V^2 / R which shows that the power loss goes as the square of the voltage. By using a step down transformer, we can minimize the power loss that occurs during transmission.
ZM
Related Physics A Level answers
All answers ▸Describe the process of nuclear fission is induced
In the Rutherford alpha scattering experiment, most particles passed straight through the foil with little or no deflection. What can be deduced about the structure of the atom from this?
Using Newton's law of gravitation, derive a suitable formula for the escape velocity of an object at Earth's surface.
Whats the effective resistance in a parallel and series circuit with a cell and two 12 ohms resistors ?