efficiency

    Cards (20)

    • What is the concept of energy transfer discussed in the material?

      Energy can be transferred from one form into another form.
    • Why is energy not always transferred into the intended form?

      Most devices aren't 100% efficient.
    • What is efficiency in the context of energy transfer?

      • Efficiency is the proportion of input energy that is converted into useful output energy.
      • It is calculated as:
      • Efficiency = Useful Energy Output / Total Energy Input
    • How do you calculate the efficiency of a device in terms of power?

      Efficiency = Useful Power Output / Total Power Input.
    • What type of energy does a lamp convert its input energy into?
      A lamp converts electrical energy into light energy and heat energy.
    • How is light energy classified in the context of a lamp's output?

      Light energy is considered useful energy output.
    • How is heat energy classified in the context of a lamp's output?

      Heat energy is classified as waste energy or non-useful energy output.
    • If a lamp has an input energy of 300 joules and outputs 45 joules of light energy, what is its efficiency?

      The efficiency is 0.150.15.
    • If a lamp has an input energy of 300 joules and outputs 225 joules of light energy, what is its efficiency?

      The efficiency is 0.750.75.
    • How many times more efficient is the LED lamp compared to the incandescent bulb?

      The LED lamp is 5 times more efficient.
    • How do you convert efficiency from decimal to percentage?

      You multiply the decimal by 100.
    • What is a common mistake when calculating efficiency?

      A common mistake is getting the division the wrong way around.
    • What happens if you calculate efficiency incorrectly and get a value greater than 1?

      It implies that more energy is output than input, which is impossible.
    • What principle explains why energy cannot be created or destroyed?

      The conservation of energy principle.
    • If a microwave has an efficiency of 70% and a total power input of 800 watts, what is the useful power output?

      The useful power output is 560 watts560 \text{ watts}.
    • What is the relationship between waste energy and devices designed to produce heat?

      • Most devices produce waste energy, often thermal.
      • Devices like electric heaters produce thermal energy as their main function, making it useful output.
    • The concept of efficiency can be applied to individuals, organizations or systems.
    • Allocative efficiency occurs when resources are allocated in a way that maximizes overall societal welfare.
    • Productive efficiency is achieved when goods and services are produced at the lowest possible cost.
    • Efficiency = Useful Work Done / Energy Supplied
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