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 ▸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?
How does having a rotating plate in a microwave help food to be heated eavenly?
Outline the principal features of a geostationary orbit and use them to explain one use of satellites in this type of orbit.
Calculate the root mean squared speed for 16g of oxygen gas at 50(deg Celsius) and explain why we use this instead of the average velocity of all the particles.