5.2 Answers

🔋 Example 1: Flashlight

Scenario: A student turns on a battery-powered flashlight.

• Input Energy

  • • Chemical energy (in the batteries)

• Converter

  • • Electrical circuit and light bulb

• Output Energy

  • • Light energy (visible light) and thermal energy (heat from the bulb)

• Energy Transformation:

  • • Chemical → Electrical → Light + Heat

• Was energy lost/dissipated?

  • • Yes — some energy is dissipated as heat, so not all energy is used for light.

• ✅ Energy was dissipated.

🚲 Example 2: Riding a Bicycle

Scenario: A student pedals a bike on a flat surface.

• Input Energy: 

  • • Chemical energy (from food in the rider’s body)

• Converter: 

  • • Muscles + mechanical components (gears, chain)

• Output Energy: 

  • • Mechanical energy (motion of the bike), sound energy (bike noises), and heat (from friction in tires and joints)

• Energy Transformation:

  • • Chemical → Mechanical → Motion + Sound + Heat

• Was energy lost/dissipated?

  • • Yes — heat and sound are forms of energy dissipation that cannot be recovered for motion.

• ✅ Energy was dissipated.

🎶 Example 3: Bluetooth Speaker Playing Music

• Input Energy:

  • • Electrical energy (battery or plug)

• Converter: 

  • • Electronic circuits and speaker components

• Output Energy: 

  • • Sound energy (music), thermal energy (heat from electronics)

• Energy Transformation:

  • • Electrical → Sound + Heat

• Was energy dissipated?

  • • ✅ Yes — heat is a byproduct and dissipates into the surroundings.

🏀 Example 4: Bouncing a Basketball

• Input Energy: 

  • • Mechanical energy (from player's arm)

• Converter: 

  • • Ball compressing and rebounding (elastic deformation)

• Output Energy: 

  • • Mechanical energy (motion), sound energy (bouncing noise), and thermal energy (friction with air and floor)

• Energy Transformation:

  • • Mechanical → Motion + Sound + Heat

• Was energy dissipated?

  • • ✅ Yes — sound and heat energy are dissipated, so the ball doesn’t bounce back to the same height.

☀️ Example 5: Solar-Powered Calculator

• Input Energy: 

  • • Light energy (from the Sun or indoor light)

• Converter: 

  • • Solar panel

• Output Energy: 

  • • Electrical energy (used to power the calculator)

• Energy Transformation:

  • • Light → Electrical

• Was energy dissipated?

  • • ✅ Some light energy is not absorbed or is lost as heat, so not all is converted to electricity. Some dissipation occurs.