Óptica geométrica e ondas · AP Physics 2 (Modern Physics)
Simulador do efeito fotoelétrico
Simulador do efeito fotoelétrico e potencial de corte: equação quântica de Einstein
- No navegador
- Sem cadastro
- Dedução ao vivo
- Modo projetor
- Folha de exercícios A4
Janela de simulação 3D● 60 FPS
Variáveis de controle do experimento
nm
%
V
Deduções e métricas em tempo real
Energia do fóton E
--
Função trabalho W0
--
Energia cinética máxima Ek
--
Tensão de corte Uc
--
Dedução de fórmulas em tempo real
Fórmula fundamental:
--Substituição de valores:
--Estado físico: --
Exemplos clássicos e armadilhas de exame
Worked Problem
Problema: Sodium work function is 2.29eV. Does 400nm light trigger emission? Find Ek,max and stopping potential Uc.
Derivação passo a passo:
- E = hc/λ = 3.11eV > 2.29eV (yes). Max kinetic energy Ek = 3.11 - 2.29 = 0.82eV. Stopping voltage Uc = 0.82V.
Worked Problem
Problema: What 3 paradoxes doomed classical wave theory in explaining the photoelectric effect?
Derivação passo a passo:
- 1) Classical waves predicted intensity determines energy (failing threshold rule); 2) energy accumulation delays (emission was instant); 3) electron energy matched frequency not intensity.
Folha de investigação em aula e exercícios
Q1. Variant 1: If light intensity doubles at constant frequency, what happens to Ek,max and saturation current?
Answer Key: Max kinetic energy Ek remains unchanged. Saturation photocurrent doubles because photon arrival rate doubles.
Q2. Variant 2: In a plot of stopping voltage Uc vs frequency ν, what do the slope and intercepts represent?
Answer Key: Slope equals h/e (Planck constant over electron charge). Vertical intercept is -W0/e; horizontal intercept is threshold frequency ν0.
Q3. Variant 3: What modern devices utilize phototubes? What is the operating mechanism?
Answer Key: Solar panels, optical sensors, night vision, barcode scanners. Light ejects electrons, creating current that converts light into electrical signals.
Perguntas frequentes e erros comuns
Why did Einstein win the Nobel Prize for the photoelectric effect rather than relativity?
Relativity was contentious in 1921; the photoelectric quantum hypothesis was conclusively verified by Millikan's precision experiments.
If photon energy exactly equals the work function (hν = W0), does emission occur?
Yes, the electron just escapes to the surface with zero excess kinetic energy (Ek = 0) and zero launch velocity.
Why does photocurrent drop smoothly rather than abruptly as reverse voltage rises?
Emitted electrons have a velocity spread from 0 to Ek,max. Higher voltage filters out slower electrons progressively.
Is light fundamentally a wave or a stream of particles?
Light possesses wave-particle duality. Propagation exhibits wave phenomena (interference, diffraction); emission and absorption exhibit particle behavior.