• Energy Transfer: Ever wondered how your phone charges? It's all about the movement of electrons in a conductor.

  • If there's a potential difference V with current I, the energy W transferred by electrons is - W = (I × Δt ) × V.

• Electrical Power (🔌)

  • Rate of energy transfer =\(\frac {W}{Δt}\)
• Power formula, P = IV. 🌟 Fun Fact: This is why our power sockets have voltage and current ratings!

• Units

  • Power is measured in watts (W).
    • Real-world example: If a bulb consumes 1W, it's using 1 Joule every second.
  • Think of volts as how much power is transferred for every unit of current.

Example 5: Imagine you have a tiny 3V, 1.5W lamp.

• Current? I = \(\frac PV\) ​= 0.5A
• Energy in 2400s? 1.5 × 2400 = 3600J. That’s like climbing 3600 stairs in terms of energy!

Example 6: Imagine an elevator powered by a 12V battery lifting a 0.10kg weight.

• Energy = mgΔh = 1.47J
• Power = \(\frac {1.47}{7}\)0.21W
• Current? I = \(\frac PV\)​ = 0.021Aor21mA But considering efficiency, it's 44mA.

• There’s a universal language for electricity! Check page 5 of the IB DP Physics Data Booklet for these symbols.
• Cells vs. Batteries
  • Battery: Group of cells. 🔋
  • Cell: Single energy source. 🕹️
  • Tip: Drawing circuits? Show connections with dots. No dot? No connection!