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 ▸A ball is dropped from rest at a height of 2 metres. Assuming acceleration due to gravity (g) is 10m/s^2 calculate the velocity of the ball just before it hits the floor.
A water jet starts at a point X and reaches its maximum height at a point Y. Air resistance has a negligible effect on the motion of the water jet. (i) State the direction of the force acting on the jet at Y. (1 mark)
A ball is kicked from a tower (50m) at a speed of 20m/s. How far away does the ball hit the ground?
Why does a feather fall at the same rate as a hammer on the Moon?