Efficiency

    Cards (19)

    • What can energy be transferred into?
      Different forms of energy
    • Why are most devices not 100% efficient?
      They lose energy in non-useful forms
    • What is efficiency in terms of energy output?
      • Proportion of input energy converted to useful output
      • Useful energy output vs. total energy input
    • What is the useful energy output of a lamp?
      Light energy
    • How is heat energy classified in a lamp's output?
      As waste energy or non-useful energy
    • What is the formula for calculating efficiency?
      Efficiency = useful energy output / total energy input
    • How can efficiency be calculated in terms of power?
      Efficiency = useful power output / total power input
    • If a lamp has an input of 300 joules and outputs 45 joules of light, what is its efficiency?
      0.15
    • If a lamp has an input of 300 joules and outputs 225 joules of light, what is its efficiency?
      0.75
    • How many times more efficient is the LED lamp compared to the incandescent bulb?
      5 times
    • How do you convert efficiency from decimal to percentage?
      Multiply by 100
    • What is a common mistake when calculating efficiency?
      Getting the division the wrong way around
    • What happens if you calculate efficiency incorrectly and get a value over 1?
      It implies more energy output than input
    • What principle states that energy can only be transferred?
      Conservation of energy principle
    • If a microwave is 70% efficient with a total power input of 800 watts, what is the useful power output?
      560 watts
    • What is the relationship between efficiency and waste energy?
      • No device is 100% efficient
      • All devices produce waste energy
      • Thermal energy is a common waste form
    • What is an exception to the rule of devices not being 100% efficient?
      Devices designed to produce heat
    • What type of energy do electric heaters produce?
      Thermal energy
    • How is thermal waste energy classified in heating devices?
      As useful output
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