Atomic Spectra & Bohr Model Challenge
25 NEET-standard questions on emission and absorption line spectra, the Balmer formula, the three Bohr postulates, orbit radius, speed and the K, U, E energies of hydrogen. 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. 12 · pp. 296–299Keys: A–D or 1–4 to answer
🧠 Formula memory tricks (open before you start)
Line spectraEmission = bright lines on dark. Absorption = dark lines on bright, at the same wavelengths.Each element has its own set of lines: a fingerprint
Balmer1/λ = R(1/2² − 1/n²)R = 1.097×10⁷ m⁻¹. n = 3 gives 656 nm, limit 365 nm
Bohr postulatesStationary orbits (no radiation) · L = nh/2π · hν = Ei − Ef
Hydrogen orbitrₙ = n² a₀, a₀ = 0.53 Å · vₙ ∝ 1/nspeed falls, radius grows
Energy tripleK = −E · U = 2E · E = −e²/8πε₀rEₙ = −13.6/n² eV
Photonλ(nm) ≈ 1243 / ΔE(eV)ionisation from n: 13.6/n² eV
right first tryfixed after explanationstill to fix
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