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level: Energy transfer in circuits

Questions and Answers List

level questions: Energy transfer in circuits

QuestionAnswer
The flow of electric charge in a circuit.Electric Currents
What do electric currents cause in a circuit?Energy Transfers.
The opposition to the flow of electric current.Resistance
What happens when current flows through a circuit with resistance?Work is done against the resistance.
The transfer of energy resulting from the application of force.Work Done
How is energy transferred in a circuit with resistance?Through the work done against the resistance.
The production of heat as a result of electric current passing through a conductor.Heating Effect
What is the primary energy transfer in a circuit with resistance?Heating.
The energy stored in the form of heat.Thermal Energy Stores
Where is the energy transferred in a circuit with resistance stored?In the thermal energy stores of the surroundings.
Energy transfer that serves a purpose or performs work.Useful Energy Transfer
In what devices is the heating effect of electric currents a useful energy transfer?Kettles, heaters, toasters.
Energy transfer that does not serve a purpose or perform useful work.Non-useful Energy Transfer
In what devices is the heating effect of electric currents a non-useful energy transfer?Computers, phones.
Energy that is scattered and spread out in the surroundings.Dissipated Energy
Where does the energy transferred in a non-useful energy transfer go?It is dissipated into the thermal energy stores of the surroundings.
The ratio of useful energy output to total energy input.Energy Efficiency
How does the concept of energy efficiency relate to useful and non-useful energy transfers in devices?Energy efficiency is higher when more energy is transferred for useful work and less is dissipated as non-useful heat.
Materials through which electric current can flow.Conductors
What is the typical atomic structure of metals?A lattice of ions with delocalised electrons.
Ions arranged in a regular, repeating pattern.Lattice Ions
What surrounds the lattice ions in metals?Delocalised Electrons.
Electrons that are not fixed to a particular atom and can move freely within a material.Delocalised Electrons.
What happens when a potential difference is applied to a metal conductor?Delocalised electrons begin to flow.
The flow of electric charge, usually carried by electrons.Electric Currents
What causes a transfer of energy in a metal conductor carrying current?Collisions between electrons and lattice ions.
Interactions between particles that result in changes in their motion.Collisions
What happens to the lattice ions when electrons collide with them in a metal conductor?The lattice ions vibrate more.
Rapid movements back and forth or oscillations.Vibrations
What effect do increased vibrations of lattice ions have on the metal conductor?It heats up.
The transfer of thermal energy.Heat
What determines the magnitude of energy transfer in a metal conductor carrying a current?The current; the bigger the current, the greater the transfer of energy.
The rate at which electrons move through a conductor.Electron Speed
How does the speed of electrons relate to the number of collisions and energy transfer in a conductor carrying a current?The faster the electrons move, the more collisions and greater the energy transfer.
The movement of energy from one place to another.Energy Transfers.
What is the primary mechanism of energy transfer in a metal conductor carrying a current?Collisions between electrons and lattice ions, leading to increased vibrations and heating.
Energy losses that occur in a system and are not useful for the intended purpose.Unwanted Energy Transfers
What causes unwanted energy transfers in electrical systems?Resistance in wires leading to heating and energy loss.
The opposition to the flow of electric current in a conductor.Resistance
Why do wires heat up and lose energy when electricity is transferred over long distances?Due to the resistance in the wires.
Materials or wires that offer less opposition to the flow of electric current.Low Resistance
How can unwanted energy transfers be reduced in electrical systems?By using low resistance wires.
Metals like copper and aluminium, which have lower resistance due to the spacing of lattice ions.Metals with Low Resistance
Why do metals like copper and aluminium have lower resistance compared to others?Lattice ions are further apart in these metals.
Wires with a larger cross-sectional area.Thick Wires
How does the thickness of a wire affect its resistance?Thick wires have lower resistance compared to thin wires.
A network of electricity transmission lines, substations, transformers, and more, used for the distribution of electrical power on a large scale.National Grid
What type of wires does the National Grid use to reduce energy loss?Thick wires made of aluminium.
The ratio of useful energy output to the total energy input in an electrical system.Electrical Efficiency
How does using low resistance wires contribute to electrical efficiency?It reduces energy losses in the form of heat.
The measure of the extent of a surface within a plane.Cross-Sectional Area
What does the thickness of a wire refer to in terms of its cross-sectional area?A larger cross-sectional area corresponds to a thicker wire.
The amount of energy transferred by an electric circuit.Electrical Energy
What is the equation for calculating electrical energy?Electrical Energy (E) = Current (I) × Voltage (V) × Time (t).
The flow of electric charge in a circuit, measured in amperes (A).Current (I)
What is the unit of measurement for current?Amperes (A).
The electric potential difference between two points in a circuit, measured in volts (V).Voltage (V)
What is the unit of measurement for voltage?Volts (V).
The duration for which current flows in a circuit, measured in seconds (s).Time (t)
What is the unit of measurement for time in electrical energy calculations?Seconds (s).
Calculate the electrical energy transferred if a kettle takes 90 seconds to boil with a current of 9 A and a potential difference of 230 V.Electrical Energy (E) = 9 A × 230 V × 90 s = 186,300 J (joules).
The rate at which electrical energy is transferred or used, measured in watts (W).Electrical Power
How is electrical power related to electrical energy?Power (P) = Energy (E) ÷ Time (t).
The process of converting one unit of measurement to another.Unit Conversion
How is joules (J) converted to kilowatt-hours (kWh)?Divide the energy in joules by 3,600,000 (1 kWh = 3,600,000 J).
Why is it important to calculate electrical energy in real-life scenarios?To assess energy consumption, costs, and efficiency of electrical devices.