Q.1 Who proposed the quantum theory of light explaining the photoelectric effect?
Albert Einstein
Max Planck
Niels Bohr
Erwin Schrödinger
Explanation - Albert Einstein explained the photoelectric effect by proposing that light is quantized in packets called photons.
Correct answer is: Albert Einstein
Q.2 What is the de Broglie wavelength associated with a particle of momentum p?
h / p
p / h
h * p
√(h/p)
Explanation - According to de Broglie, the wavelength λ of a particle is given by λ = h/p, where h is Planck's constant and p is momentum.
Correct answer is: h / p
Q.3 Which experiment confirmed the wave nature of electrons?
Rutherford scattering
Davisson-Germer experiment
Millikan oil drop
Photoelectric experiment
Explanation - The Davisson-Germer experiment demonstrated electron diffraction, confirming the wave nature of electrons.
Correct answer is: Davisson-Germer experiment
Q.4 The energy levels of a hydrogen atom are given by which formula?
-13.6 / n
-13.6 / n²
-13.6 * n²
-13.6 * n
Explanation - The Bohr model gives the energy levels of hydrogen as E_n = -13.6 eV / n², where n is the principal quantum number.
Correct answer is: -13.6 / n²
Q.5 Which principle states that it is impossible to simultaneously know the exact position and momentum of a particle?
Pauli exclusion principle
Heisenberg uncertainty principle
Bohr correspondence principle
de Broglie hypothesis
Explanation - The Heisenberg uncertainty principle states Δx·Δp ≥ ħ/2, limiting simultaneous knowledge of position and momentum.
Correct answer is: Heisenberg uncertainty principle
Q.6 Which particle mediates the electromagnetic force?
Photon
Electron
Proton
Neutrino
Explanation - The photon is the quantum of the electromagnetic field and mediates the electromagnetic force.
Correct answer is: Photon
Q.7 What is the binding energy of a nucleus?
Energy required to form the nucleus
Energy required to split the nucleus into nucleons
Energy released in nuclear decay
Energy of emitted photons
Explanation - Binding energy is the energy needed to separate a nucleus into its constituent protons and neutrons.
Correct answer is: Energy required to split the nucleus into nucleons
Q.8 Which phenomenon demonstrates the particle nature of light?
Diffraction
Interference
Photoelectric effect
Refraction
Explanation - The photoelectric effect shows that light behaves as discrete photons transferring energy to electrons.
Correct answer is: Photoelectric effect
Q.9 In nuclear reactions, mass defect refers to:
Difference between proton and neutron mass
Difference between initial and final mass of nucleus
Mass of the emitted alpha particle
Mass of electrons in the atom
Explanation - Mass defect is the difference between the sum of individual nucleon masses and the actual mass of the nucleus, corresponding to binding energy.
Correct answer is: Difference between initial and final mass of nucleus
Q.10 Which law explains blackbody radiation and introduced the concept of quantization?
Planck's law
Newton's law
Ohm's law
Boyle's law
Explanation - Planck's law describes blackbody radiation and introduced energy quantization to solve the ultraviolet catastrophe problem.
Correct answer is: Planck's law
Q.11 What is the approximate speed of a gamma photon in vacuum?
0 m/s
3 × 10^8 m/s
1 × 10^6 m/s
Depends on wavelength
Explanation - All electromagnetic radiation, including gamma photons, travels at the speed of light (c ≈ 3 × 10^8 m/s) in vacuum.
Correct answer is: 3 × 10^8 m/s
Q.12 Which model of the atom first incorporated quantized orbits for electrons?
Rutherford model
Bohr model
Thomson model
Schrödinger model
Explanation - Bohr introduced quantized orbits to explain discrete atomic spectra, unlike Rutherford's classical model.
Correct answer is: Bohr model
Q.13 Which particle has an associated antiparticle called positron?
Electron
Proton
Neutron
Photon
Explanation - The electron's antiparticle is the positron, having the same mass but opposite charge.
Correct answer is: Electron
Q.14 Which of the following is a radioactive decay process emitting a beta particle?
Alpha decay
Beta decay
Gamma decay
Neutron decay
Explanation - Beta decay involves emission of a beta particle (electron or positron) from the nucleus.
Correct answer is: Beta decay
Q.15 Which equation represents Einstein's mass-energy equivalence?
E = mc²
E = hv
F = ma
p = mv
Explanation - Einstein's famous equation E = mc² shows that mass can be converted into energy and vice versa.
Correct answer is: E = mc²
Q.16 Which scientist developed the Schrödinger equation?
Werner Heisenberg
Erwin Schrödinger
Niels Bohr
Paul Dirac
Explanation - Erwin Schrödinger formulated the wave equation describing quantum systems probabilistically.
Correct answer is: Erwin Schrödinger
Q.17 Which phenomenon is explained by wave-particle duality?
Interference and diffraction of electrons
Reflection of light
Gravitational attraction
Ohm's law in conductors
Explanation - Wave-particle duality shows that particles like electrons exhibit both wave-like (diffraction/interference) and particle-like properties.
Correct answer is: Interference and diffraction of electrons
Q.18 What is the main limitation of Rutherford's model of the atom?
It did not explain discrete spectral lines
It assumed quantized orbits
It included electrons in clouds
It ignored nuclear charge
Explanation - Rutherford's model could not explain why atoms emit only specific spectral lines; Bohr's quantization resolved this.
Correct answer is: It did not explain discrete spectral lines
Q.19 What type of radiation is emitted during gamma decay?
Electron
Proton
Photon
Neutron
Explanation - Gamma decay involves the emission of high-energy photons without changing the number of protons or neutrons in the nucleus.
Correct answer is: Photon
Q.20 What is Planck’s constant approximately?
6.626 × 10^-34 Js
3 × 10^8 m/s
1.6 × 10^-19 C
9.11 × 10^-31 kg
Explanation - Planck’s constant (h) is 6.626 × 10^-34 Js, fundamental in quantization of energy.
Correct answer is: 6.626 × 10^-34 Js
Q.21 Which principle states that no two electrons can occupy the same quantum state in an atom?
Pauli exclusion principle
Heisenberg uncertainty principle
Bohr correspondence principle
de Broglie hypothesis
Explanation - The Pauli exclusion principle prevents two electrons in an atom from having the same set of quantum numbers.
Correct answer is: Pauli exclusion principle
Q.22 Which particle is electrically neutral and resides in the nucleus?
Proton
Electron
Neutron
Positron
Explanation - Neutrons are neutral particles located in the nucleus along with protons.
Correct answer is: Neutron
Q.23 Which scientist proposed the uncertainty principle in quantum mechanics?
Niels Bohr
Werner Heisenberg
Max Planck
Louis de Broglie
Explanation - Werner Heisenberg proposed the uncertainty principle, limiting simultaneous measurement of position and momentum.
Correct answer is: Werner Heisenberg
Q.24 Which of the following is an application of nuclear physics?
Medical imaging
Optical lens manufacturing
Mechanical gears
Chemical bonding
Explanation - Nuclear physics is applied in medical imaging techniques like PET scans, which use radioactive isotopes.
Correct answer is: Medical imaging