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 ▸What is a stationary wave?
A nucleus of the stable isotope Pb(208,82) has more neutrons than protons. Explain why there is this imbalance between proton and neutron numbers by referring to the forces that operate within the nucleus.
How can an object be accelerating when it's velocity is constant, and how does centripetal acceleration work.
Light with a frequency of 200nm is shone on a sodium plate with a work function of 2.28eV and electrons start escaping the surface of the plate due to the photoelectric effect. What is the maximum kinetic energy of one of these electrons in eV?