1.2.2 Efficiency of Energy Transfers

• Efficiency measures how much of the input energy is converted into useful output energy.
• If a motor consumes 100J of electrical energy and delivers 80J of mechanical work, what is its efficiency?

  80%
• What is often wasted energy lost as?

  Heat, sound, or light
• A motor consuming 100J and delivering 80J has an efficiency of 80%.


  True
• What is the unit used to measure energy in efficiency calculations?

  Joules
• What is an example of useful energy?

  Kinetic energy of a car
• The efficiency of an energy transfer system measures how well it converts input energy into useful output energy.


  True
• What is the efficiency of a motor that consumes 100J and delivers 80J of work?

  80%
• When calculating efficiency, it is important to use the same units for input and output energy.


  True
• To calculate efficiency, we use the formula: Efficiency = (Useful Output Energy / Total Input Energy) × 100%
• When calculating efficiency, it is necessary to use the same units for input and output energy.


  True
• Energy lost as heat, sound, or other forms of waste reduces the overall efficiency
• What is energy transfer?

  Moving energy from one form
• What is wasted energy in energy transfers?

  Energy not contributing to task
• What is the formula for efficiency in energy transfers?

  Efficiency = \frac{\text{Useful Output Energy}}{\text{Total Input Energy}} \times 100\%</latex>
• If a motor consumes 100J of electrical energy and delivers 80J of mechanical work, what is its efficiency?

  80%
• Efficiency is calculated as (Useful Output Energy / Total Input Energy) × 100%
• What is the efficiency of a motor that consumes 100J of electrical energy and delivers 80J of mechanical work?

  80%
• Match the device with its approximate efficiency:

  Light Bulb ↔️ 10%

  Electric Motor ↔️ 70%

  Solar Panel ↔️ 20%

  Gas Boiler ↔️ 80%
• Energy losses such as heat or sound reduce efficiency.


  True
• What is imperfect conversion in energy transfer processes?

  Failure to convert input energy completely
• What is the definition of energy transfer?

  Moving energy from one place
• The formula for efficiency is (Useful Output Energy / Total Input Energy) × 100%


  True
• Match the energy type with its characteristics:

  Useful Energy ↔️ Contributes to the desired task

  Wasted Energy ↔️ Does not contribute to task
• Efficiency is calculated as the ratio of useful output energy to total input energy multiplied by 100%.
• What is the formula for efficiency in energy transfer?

  Efficiency = (Output / Input) × 100%
• In an energy transfer process, we distinguish between useful energy and wasted energy.wasted.
• Match the energy type with its characteristics:

  Useful Energy ↔️ Contributes to desired task

  Wasted Energy ↔️ Does not contribute to task
• How is efficiency expressed in calculations?

  As a percentage
• Order the devices from highest to lowest efficiency:

  1️⃣ Gas Boiler

  2️⃣ Electric Motor

  3️⃣ Solar Panel

  4️⃣ Light Bulb
• To calculate efficiency, we use the formula: (Useful Output Energy / Total Input Energy) × 100%.
• What is the efficiency of a solar panel that absorbs 200J of solar energy and converts 40J into electrical energy?

  20%
• What is one key factor that affects the efficiency of energy transfer processes?

  Energy losses
• Match the factor affecting efficiency with its example:

  Energy Losses ↔️ Heat from a car engine

  Friction and Resistance ↔️ Resistance in wires

  Imperfect Conversion ↔️ Solar panel's energy conversion
• Efficiency measures how much of the input energy is converted into useful output energy
• Wasted energy is often lost as heat, sound, or light.

  True
• In the efficiency formula, the numerator represents the useful output energy
• What is efficiency a measure of?

  Energy transfer conversion
• The denominator in the efficiency formula represents the total input energy.


  True
• In the motor example, 80% of the input energy was converted into useful mechanical output energy