The Modern Physics 1 category gathers practice questions that focus on key concepts introduced in modern physics. Topics include the fundamentals of relativity, basic quantum mechanics, and atomic structure, helping students reinforce their understanding and prepare for exams.
1080 is correct per Radioactive material decays by simultane principle; validated by standard physics law.
Ref: NCERT Physics Class 12 Chapter 13 Nuclei
After 9h =3 half-lives, remaining N=N0/2^3=N0/8.
Ref: NCERT Physics Class 12 Chapter 13 Nuclei
Alpha decay: mass number 4, atomic number 2, X is alpha particle ^4He2.
Ref: NCERT Physics Class 12 Chapter 13 Nuclei
Alpha reduces A by 4 Z by 2, beta increases Z by 1 each, net A-4 Z same.
Ref: NCERT Physics Class 12 Chapter 13 Nuclei
Mass defect Δm=E/931.5=2.23/931.5≈0.00239 amu.
Ref: NCERT Physics Class 12 Chapter 13 Nuclei
Lyman series corresponds to UV region, Balmer visible, Paschen IR.
Ref: NCERT Physics Class 12 Chapter 12 Atoms
Bohr orbits stationary because angular momentum quantized, no radiation despite acceleration.
Ref: NCERT Physics Class 12 Chapter 12 Atoms
Rutherford bombarded thin gold foil with alpha particles, observed large angle scattering.
Ref: NCERT Physics Class 12 Chapter 12 Atoms
Fusion requires high temperature and pressure to overcome Coulomb barrier, ~10^7 K.
Ref: NCERT Physics Class 12 Chapter 13 Nuclei
λ_e=h/√(2mE), λ_ph=hc/E, ratio λ_e/λ_ph=√(E/2mc^2) etc.
Ref: NCERT Physics Class 12 Chapter 11 Dual Nature of Radiation and Matter
λ=h/√(2mE), shortest wavelength heaviest mass α particle, mα largest.
Ref: NCERT Physics Class 12 Chapter 13 Nuclei
Statement false: wave theory cannot explain photoelectric effect; particle theory does.
Ref: NCERT Physics Class 12 Chapter 11 Dual Nature of Radiation and Matter
