Eletricidade e eletromagnetismo · GCSE Physics Topic 4 (Electricity & Power)
Simulador de potência elétrica e brilho de lâmpadas
Simulador de potência nominal vs real e brilho de lâmpadas em série e paralelo
- No navegador
- Sem cadastro
- Dedução ao vivo
- Modo projetor
- Folha de exercícios A4
Janela de simulação 3D● 60 FPS
Variáveis de controle do experimento
V
W
W
Deduções e métricas em tempo real
Potência real lâmpada 1
--
Potência real lâmpada 2
--
Resistência lâmpada 1 R1
--
Resistência lâmpada 2 R2
--
Dedução de fórmulas em tempo real
Fórmula fundamental:
--Substituição de valores:
--Estado físico: --
Versão para o fundamental:🎮 Acenda a lâmpada: circuitos simples ↗
Exemplos clássicos e armadilhas de exame
Worked Problem
Problema: Bulbs L1 (6V 3W) and L2 (6V 6W) wired in series across 9V. Which lights normally? Does either burn out?
Derivação passo a passo:
- I1_rated = 0.5A, R1 = 12Ω. I2_rated = 1.0A, R2 = 6Ω. Series current I = 9/(12+6) = 0.5A. L1 operates at rated 0.5A normally; L2 operates dimly; neither burns.
Worked Problem
Problema: An electric meter reads 3000 rev/(kW·h). A kettle alone turns disk 150 rev in 3 min. Find its actual electrical power.
Derivação passo a passo:
- Energy consumed W = 150/3000 = 0.05 kW·h = 180 kJ. Time t = 180s. Actual power P = W/t = 180,000/180 = 1000W.
Folha de investigação em aula e exercícios
Q1. Variant 1: Comparing 220V 40W and 220V 100W incandescent bulbs, which filament is thicker?
Answer Key: From R = U²/P, higher power requires lower resistance. The 100W bulb has lower resistance and a thicker, shorter tungsten filament.
Q2. Variant 2: In measuring bulb power, can multiple trial wattages be averaged as "rated power"? Why?
Answer Key: Never! Actual power varies with voltage. Rated power is defined strictly at rated voltage. Averaging different voltage trials is physically meaningless.
Q3. Variant 3: Why do incandescent lightbulbs almost always burn out the instant they are switched on?
Answer Key: Cold tungsten has 10x lower resistance than at operating temperature. Turning it on creates a massive 10x current surge that blows weak spots.
Perguntas frequentes e erros comuns
Is "kWh" a unit of power or energy? How many Joules is 1 kWh?
Energy! 1 kWh = 1000W * 3600s = 3.6*10^6 Joules (3.6 MJ). It powers a 100W bulb for 10 hours.
Why are LED bulbs far more energy-efficient than incandescent bulbs?
Incandescent bulbs waste >90% of electricity as invisible thermal infrared heat. LEDs generate light via solid-state electroluminescence at >50% efficiency.
To connect two 110V bulbs in series across 220V, what condition must hold?
Their rated wattages must be strictly identical! Otherwise unequal resistances split voltage unequally, overvolting and blowing the higher-resistance bulb.
Do household appliances consume power in standby mode?
Yes! Internal power transformers and microcontrollers remain energized, drawing 0.5W to 5W per device continuously (phantom load).