Ans. The important formulas in Modern Physics I & II include:- Einstein's mass-energy equivalence formula: E = mc^2- Planck's energy quantization formula: E = hf- de Broglie wavelength formula: λ = h/p- Schrödinger equation: Ĥψ = Eψ- Heisenberg's uncertainty principle: ΔxΔp ≥ h/4π