Energy

• Energy stores


  chemical, kinetic, gravitational, elastic, thermal, magnetic,

  electrostatic, nuclear
• Energy transfers


  Mechanically, electrically,

  by heating, by radiation
• Equation for work done

  work done = force × distance moved
• work done is equal to energy transferred
• Equation for efficiency


  efficiency = (useful energy output/total energy input) x 100%
• Three thermal energy transfers

  Conduction, convection and radiation
• Equation for gravitational potential energy

  gravitational potential energy =

  mass × gravitational field strength × height
• Equation for kinetic energy

  kinetic energy = ½ × mass × speed 2
• What is power?


  the rate of transfer of energy or the rate of work done
• Equation for power


  power = work done / time taken
• Ways of generating electricity:

  • wind

  ● water

  ● geothermal resources

  ● solar heating systems

  ● solar cells

  ● fossil fuels

  ● nuclear power
• What are the different forms of energy mentioned in the study material?

  Kinetic, Gravitational Potential, Elastic Potential, Thermal, Chemical, Electrical, Nuclear, Sound, and Light Energy
• What is Kinetic Energy (KE) and how is it calculated?


  Kinetic Energy is energy due to motion, calculated as $KE =$$\frac{1}{2} mv^2$
• What does the variable $m$ represent in the Kinetic Energy formula?


  $m$ represents the mass in kilograms
• What does the variable $v$ represent in the Kinetic Energy formula?


  $v$ represents the velocity in meters per second (m/s)
• What is Gravitational Potential Energy (GPE) and how is it calculated?


  Gravitational Potential Energy is energy stored due to height, calculated as $GPE =$$mgh$
• What does the variable $g$ represent in the Gravitational Potential Energy formula?


  $g$ represents the gravitational field strength, which is 9.8 m/s² on Earth
• What does the variable $h$ represent in the Gravitational Potential Energy formula?


  $h$ represents the height in meters
• What is Elastic Potential Energy?


  Elastic Potential Energy is energy stored in stretched or compressed objects like springs
• What is Thermal Energy?


  Thermal Energy is energy due to the temperature of an object, related to the kinetic energy of its particles
• What is Chemical Energy?


  Chemical Energy is energy stored in the bonds of chemical compounds, like food, fuels, and batteries
• What is Electrical Energy?


  Electrical Energy is energy due to the flow of electric charge (current)
• What is Nuclear Energy?


  Nuclear Energy is energy stored in the nucleus of atoms, released in nuclear reactions
• What is Sound Energy?


  Sound Energy is energy carried by sound waves
• What is Light Energy?


  Light Energy is energy carried by electromagnetic waves (light)
• What is the Law of Conservation of Energy?


  The Law of Conservation of Energy states that energy cannot be created or destroyed, only transferred or transformed
• What does the equation $Total \ Energy \ Input =$$Total \ Energy \ Output$ represent?


  It represents the conservation of energy in a closed system
• Why is energy often lost to the surroundings?


  Energy is often lost to the surroundings as heat due to friction, air resistance, etc.
• What are the methods of energy transfer?


  Energy can be transferred mechanically, electrically, by heating, or by radiation
• How is energy transferred when boiling water in a kettle?

  Electrical energy is transferred into thermal energy, which heats the water
• What is Work Done in terms of energy transfer?


  Work Done describes energy transfer when a force moves an object
• How is Work Done calculated?


  Work Done is calculated as $W =$$F \times d$
• What are the units for Work Done, Force, and Distance?


  Work Done is in Joules (J), Force in Newtons (N), and Distance in meters (m)
• What is Power in terms of energy transfer?


  Power is the rate of doing work or transferring energy
• How is Power calculated?


  Power is calculated as $P =$$\frac{W}{t}$
• What is the unit of Power?


  Power is measured in Watts (W)
• What is the relationship between Kinetic Energy and Gravitational Potential Energy?


  Kinetic Energy and Gravitational Potential Energy can interchange; as one increases, the other decreases
• What is Efficiency in energy transfer?


  Efficiency measures how much input energy is usefully transferred in a process
• How is Efficiency calculated?


  Efficiency is calculated as $Efficiency =$$\frac{Useful \ Energy \ Output}{Total \ Energy \ Input} \times 100$
• Why is Efficiency always less than 100%?


  Efficiency is always less than 100% because some energy is lost, usually as heat, sound, or light