6. Generating and Distributing Electricity and Household Use Flashcards
What is induced across the ends of a conductor when it moves relative to a magnetic field or is in a changing magnetic field?
A potential difference (pd) is induced across the ends of a conductor.
What is the term used to describe the phenomenon where a potential difference is induced across the ends of a conductor when it moves relative to a magnetic field or is in a changing magnetic field?
The generator effect.
What factors affect the size of the induced potential difference in a conductor?
The size of the induced potential difference increases with:
Increased speed of movement
Increased strength of the magnetic field
Increased number of turns on the coil
Increased area of the coil.
How do power stations generate electricity?
Power stations use turbines to turn wire coils between magnets to generate electricity.
What is the purpose of transformers in electricity transmission and distribution?
Transformers are used to change the voltage levels in the distribution network, stepping up the voltage for transmission and stepping down the voltage for local consumers.
What is the purpose of a step-up transformer?
In a step-up transformer, the potential difference across the secondary coil is greater than the potential difference across the primary coil.
What is the purpose of a step-down transformer?
In a step-down transformer, the potential difference across the secondary coil is less than the potential difference across the primary coil.
What is a switch mode transformer?
Switch mode transformers operate at high frequencies, are smaller and lighter than traditional transformers, and are useful for applications such as mobile phone chargers.
What is the basic structure of a transformer?
A transformer consists of a primary coil and a secondary coil wound on a soft iron core.
What happens to the induced potential difference and current flow in a conductor when the direction of motion or the polarity of the magnet is reversed?
The polarity of the induced potential difference and direction of flow of any induced current are reversed.
What safety feature can disconnect a circuit in case of an electrical fault?
A fuse or a circuit breaker in the live wire can disconnect the circuit in case of an electrical fault.
What is the motor effect?
The motor effect occurs when a current-carrying conductor experiences a force in a magnetic field, resulting in motion.
How is energy transferred by an appliance measured?
The rate at which energy is transferred by an appliance is called power, measured in watts (W).
What is the relationship between power, energy transferred, and time?
The relationship is: P = E/t
What unit is often used to measure energy transfers in domestic appliances?
Energy transfers in domestic appliances are often measured in kilowatt-hours (kWh).
