| Cue Column | Note Column |
|---|---|
| What is c = νλ? | Speed of light equation: c = m/s equals frequency × wavelength. All EM radiation travels at c in vacuum. |
| Planck's constant value? | h = J·s. Energy per photon: E = hν = hc/λ. |
| Photoelectric effect — who explained it? | Einstein (1905). Light consists of photons. Each photon has energy hν. |
| What is threshold frequency ν_{0}? | Minimum frequency to eject an electron. Below ν_{0}: NO emission, regardless of intensity. |
| KE formula for photoelectrons? | KE = hν − hν_{0}. If ν < ν_{0}: KE would be negative (impossible), so no emission. |
| Effect of intensity above ν_{0}? | More photons = more electrons. Intensity does NOT change KE. |
| Work function φ? | φ = hν_{0}. Energy needed to overcome metal's binding of surface electron. |
Diagram: Photoelectric effect apparatus
Summary: Energy is quantized (E = hν). The photoelectric effect proves light's particle nature (photons). KE of electrons depends only on frequency; intensity only affects the count of ejected electrons. No emission below threshold frequency.