Atoms Class 12 Physics Notes – Formulas & Quick Revision

Atoms chapter mein Rutherford model, Bohr model aur hydrogen spectrum aate hain. Yahan aapko is chapter ke sabse important formulas aur quick revision points free milte hain — NCERT/CBSE syllabus ke hisaab se, boards aur JEE/NEET dono ke liye.

Important Formulas & Concepts — Atoms

• rₙ = 0.529·n²/Z Å
• Eₙ = −13.6·Z²/n² eV
• vₙ = 2.18 × 10⁶·Z/n m/s
• 1/λ = R·Z²(1/n₁² − 1/n₂²); R = 1.097 × 10⁷ m⁻¹
• Lyman (n→1, UV), Balmer (n→2, visible), Paschen (n→3, IR)
• Angular momentum: mvr = nh/2π
• Ionisation energy of H = 13.6 eV
• Number of spectral lines = n(n−1)/2

Quick Revision Points

• Ground state energy −13.6 eV; excited states kam negative
• Energy absorb → upar jump; emit → neeche
• Balmer series ki pehli line Hα (656 nm, red)
• Bohr model sirf single-electron species ke liye (H, He⁺, Li²⁺)
• Distance of closest approach: alpha-particle scattering

FAQ

Spectrum numericals kaise karu?

Rydberg formula mein n₁, n₂ series se identify karo — PDF mein series map bana hai.

Bohr postulates rate hain?

Teen postulates — PDF mein diagram ke saath simple language mein diye hain.

Explore more: free sample notes, free calculators aur interactive simulators.