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 the difference between a scalar and a vector?
If the highest frequency a song is 10 kHz and it is encoded at 16 bits per sample what is the minimum number of bytes needed to encode the 3 minute song?
In a circuit with a thermistor and bulb, what happens to the brightness of the bulb as the temperature increases?
A stationary particle explodes into 3: A (to the left), B and C (both to the right). B has mass m and speed 3v. C has mass 2m and speed v. A has speed 2v. What is the mass of A in terms of m?