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 ▸Derive an expression for the centripetal acceleration of a body in uniform circular motion.
How do you use a Variable Resistor to determine values to show the relationship between I and V?
How do you combine resistors is series and parallel?
An ideal gas within a closed system undergoes an isothermal expansion from an initial volume of 1m^3 to 2m^3. Given that the initial pressure of the gas is 10^5 Pa, find the final pressure of the gas following the expansion.