Photon & Einstein’s Equation Challenge
25 NEET-standard questions on how Einstein’s equation explains the photoelectric facts, the V₀–ν line and Millikan, and the photon: its energy, momentum, intensity as photon flux, and conservation in collisions. Answer each one. If you get it wrong, Vidya Ma’am explains it with an animated movie you can control, a slider to play with, and a step-by-step solution. Then try again.
NCERT Physics XII Part II · Ch. 11 · pp. 282–284Keys: A–D or 1–4 to answer
🧠 Formula memory tricks (open before you start)
“Frequency decides energy”Kmax = hν − φ₀ depends on ν only. Intensity changes the number of electrons, never their K.
Thresholdν₀ = φ₀/hbelow ν₀: no emission, however intense or long
Stopping potential lineV₀ = (h/e)ν − φ₀/eslope = h/e (same for all metals); h = e × slope
PhotonE = hν = hc/λp = hν/c = h/λ, speed c, E = pc
Photon countN = P/(hν)intensity = photons per area per second × hν
CollisionsEnergy and momentum conserved. Photon number need not be.
NeutralPhotons carry no charge, so E and B fields do not deflect them.
right first tryfixed after explanationstill to fix
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