Edexcel GCSE Magnetism & Electromagnetism - transformers

What is the main function of a transformer?

• Cook food in the kitchen

• Play music in the living room

• Change voltage level of AC circuit

• Drive a car on the highway

State Faraday's law of electromagnetic induction.

• The induced emf in a closed circuit is equal to the current flowing through the circuit

• Faraday's law only applies to AC circuits

• The induced emf in a closed circuit is equal to the resistance of the circuit

• The induced emf in a closed circuit is equal to the rate of change of magnetic flux through the circuit.

Explain how the National Grid works.

• The National Grid functions by transmitting water from power stations to substations for energy distribution.

• The National Grid works by transmitting electricity from power stations to substations at high voltages, then reducing the voltage through transformers for distribution to homes and businesses.

• The National Grid operates by storing electricity in large batteries for distribution.

• The National Grid works by using wind power exclusively for electricity transmission.

What is the purpose of step-up transformers in the National Grid?

• To store excess electricity for future use

• To decrease the voltage of electricity before transmitting it over long distances

• To increase the voltage of electricity before transmitting it over long distances

• To convert electricity into mechanical energy

Why is alternating current (AC) used in the National Grid?

• Efficient long-distance transmission and safe distribution

• To make the grid less efficient

• To create safety hazards

• To increase pollution levels

Fill in the blank: The voltage in the National Grid is stepped up to reduce ________ loss.

• transmission

• conduction

• generation

• distribution

What is the role of the Earth wire in a plug?

• Provides a path for the current to flow to the ground in case of a fault

• Provides power to the device

• Helps in data transmission

• Acts as a fuse

Describe how a transformer changes the voltage of an alternating current.

• A transformer changes the voltage of an alternating current by using chemical reactions

• A transformer changes the voltage of an alternating current by converting it into direct current

• A transformer changes the voltage of an alternating current through electromagnetic induction based on the ratio of the number of turns in the primary and secondary coils.

• A transformer changes the voltage of an alternating current by altering the frequency of the current

Why are transformers more efficient than direct current (DC) converters?

• Transformers are powered by renewable energy sources

• Direct current converters are made of superior materials

• Transformers operate on AC, which can be easily stepped up or down in voltage using electromagnetic induction, resulting in less energy loss during transmission.

• Transformers use magic to convert electricity efficiently

What is the formula to calculate power in an electrical circuit?

• P = V x I

• P = I / V

• P = V / I

• P = V + I