Three worked problems apply the efficiency formula (useful output divided by total input) to real devices: an electric water pump, a water heater, and a lamp. Each example walks through the calculation step by step, finishing with a Sankey diagram that visually splits the lamp's 100 J input into 25 J of useful light and 75 J of wasted heat. Arabic on-screen text explains each step while formulas and numbers stay in standard notation, making it useful for physics students practicing efficiency and energy-loss concepts.
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Scene 7: Practice Problems (Problems 3, 4, & 5)Problem 3 (Try A - Electric Water Pump):Prompt & Motion: Electric pump with input power of 2000 W producing 1500 W useful output power. Voiceover & Step-by-Step Breakdown:Calculation: Efficiency ($\eta$) = Useful Output / Total Input = $1500 / 2000 = 0.75 = \mathbf{75\%}$. Problem 4 (Try B - Water Heater):Prompt & Motion: Electric water heater receiving 2400 W input power and delivering 2040 W useful thermal power. Voiceover & Step-by-Step Breakdown:Calculation: Efficiency ($\eta$) = $2040 / 2400 = 0.85 = \mathbf{85\%}$. Problem 5 (Try C & D - Electric Lamp Energy & Sankey):Prompt & Motion: A lamp supplied with 100 J of electrical energy, producing 25 J of useful light and dissipating the rest as heat. Voiceover & Step-by-Step Breakdown:(A) Wasted Energy: $100\text{ J} - 25\text{ J} = \mathbf{75\text{ J}}$. (B) Efficiency: $\eta = 25 / 100 = 0.25 = \mathbf{25\%}$. (C & D) Sankey Diagram Concept: Input arrow of 100 J splits into a useful light arrow of 25 J and a wasted thermal arrow of 75 J. IMPORTANT LANGUAGE RULE: All on-screen text must be in Arabic EXCEPT mathematical equations, formulas, laws, symbols, variables, and numerical expressions. Keep every equation, formula, and law exactly as provided, without translating or changing it. Translate only the explanatory text, headings, labels, and descriptions into Arabic. Arabic text must use proper RTL direction and correct Arabic typography. Do not use English text anywhere else on the screen. Audience: student