Q.1 Who proposed the quantum theory of energy levels?
Albert Einstein
Niels Bohr
Max Planck
Erwin Schrödinger
Explanation - Max Planck introduced the idea of quantized energy levels in 1900, laying the foundation for quantum mechanics.
Correct answer is: Max Planck
Q.2 What is the speed of light in vacuum approximately?
3 × 10^8 m/s
3 × 10^6 m/s
3 × 10^5 m/s
3 × 10^7 m/s
Explanation - The universal constant speed of light in vacuum is approximately 3 × 10^8 meters per second.
Correct answer is: 3 × 10^8 m/s
Q.3 Which equation describes the energy-mass equivalence?
F = ma
E = mc^2
p = mv
V = IR
Explanation - Einstein’s special relativity established the relation E = mc^2, where energy and mass are interchangeable.
Correct answer is: E = mc^2
Q.4 The photoelectric effect provided evidence for which concept?
Wave nature of light
Particle nature of light
Diffraction of light
Polarization of light
Explanation - The photoelectric effect showed that light behaves as discrete photons, supporting the particle nature of light.
Correct answer is: Particle nature of light
Q.5 Which scientist explained the photoelectric effect using photons?
Max Planck
Albert Einstein
Werner Heisenberg
Niels Bohr
Explanation - Einstein explained the photoelectric effect in 1905 using photons, earning the Nobel Prize in Physics in 1921.
Correct answer is: Albert Einstein
Q.6 Which model of the atom introduced quantized electron orbits?
Rutherford model
Bohr model
Thomson model
Quantum mechanical model
Explanation - Niels Bohr proposed that electrons orbit the nucleus in fixed quantized paths, explaining hydrogen spectra.
Correct answer is: Bohr model
Q.7 Which principle states that position and momentum cannot be simultaneously known with absolute precision?
Exclusion principle
Superposition principle
Uncertainty principle
Equivalence principle
Explanation - Heisenberg’s Uncertainty Principle states that we cannot simultaneously know a particle’s exact position and momentum.
Correct answer is: Uncertainty principle
Q.8 What is the rest mass of a photon?
Zero
Small but finite
Infinite
Cannot be determined
Explanation - Photons have zero rest mass but possess energy and momentum due to their speed of light motion.
Correct answer is: Zero
Q.9 Which discovery led to the development of nuclear power?
Radioactivity
Superconductivity
Electromagnetism
Quantum tunneling
Explanation - The discovery of radioactivity by Henri Becquerel and later studies led to nuclear energy and power development.
Correct answer is: Radioactivity
Q.10 Which subatomic particle was discovered by J.J. Thomson?
Proton
Electron
Neutron
Photon
Explanation - J.J. Thomson discovered the electron in 1897 using cathode ray experiments.
Correct answer is: Electron
Q.11 What is the energy of a photon given by?
E = hf
E = mc^2
E = mv^2
E = IR
Explanation - Planck’s relation states photon energy is given by E = hf, where h is Planck’s constant and f is frequency.
Correct answer is: E = hf
Q.12 Who discovered the neutron?
James Chadwick
Niels Bohr
Enrico Fermi
J.J. Thomson
Explanation - James Chadwick discovered the neutron in 1932, completing the known set of subatomic particles in the atom.
Correct answer is: James Chadwick
Q.13 Which nuclear process powers the Sun?
Nuclear fission
Nuclear fusion
Radioactive decay
Beta emission
Explanation - The Sun produces energy through nuclear fusion, where hydrogen nuclei fuse to form helium, releasing energy.
Correct answer is: Nuclear fusion
Q.14 What is the SI unit of Planck’s constant?
Joule
Joule-second
Newton-meter
Watt
Explanation - Planck’s constant h has the SI unit of Joule-second (J·s).
Correct answer is: Joule-second
Q.15 Which isotope of Uranium is commonly used in nuclear reactors?
U-235
U-238
U-234
U-239
Explanation - Uranium-235 is fissile and commonly used in nuclear reactors for energy production.
Correct answer is: U-235
Q.16 X-rays were discovered by:
Wilhelm Röntgen
Marie Curie
Ernest Rutherford
Enrico Fermi
Explanation - Röntgen discovered X-rays in 1895, revolutionizing medical imaging and physics research.
Correct answer is: Wilhelm Röntgen
Q.17 Which element did Marie Curie discover?
Polonium and Radium
Uranium and Thorium
Cobalt and Nickel
Hydrogen and Helium
Explanation - Marie Curie discovered Polonium and Radium, contributing to radioactivity research.
Correct answer is: Polonium and Radium
Q.18 What does nuclear fission involve?
Combining two nuclei
Splitting of a heavy nucleus
Decay of neutrons
Emission of photons
Explanation - Nuclear fission is the splitting of a heavy nucleus into smaller nuclei with release of energy.
Correct answer is: Splitting of a heavy nucleus
Q.19 Which principle explains electron arrangement in orbitals?
Pauli Exclusion Principle
Uncertainty Principle
Relativity Principle
Equivalence Principle
Explanation - The Pauli Exclusion Principle states that no two electrons can have identical quantum numbers.
Correct answer is: Pauli Exclusion Principle
Q.20 De Broglie’s hypothesis states particles have:
Only mass
Only charge
Wave-like properties
No physical properties
Explanation - Louis de Broglie proposed that particles like electrons exhibit wave-like properties, leading to wave-particle duality.
Correct answer is: Wave-like properties
Q.21 What does a Geiger-Müller counter detect?
Electric fields
Radiation
Sound waves
Magnetic fields
Explanation - A Geiger-Müller counter detects and measures ionizing radiation.
Correct answer is: Radiation
Q.22 Which experiment confirmed the wave nature of electrons?
Davisson-Germer experiment
Millikan oil drop experiment
Gold foil experiment
Double-slit experiment with light
Explanation - The Davisson-Germer experiment showed electron diffraction, confirming their wave nature.
Correct answer is: Davisson-Germer experiment
Q.23 Who discovered radioactivity?
Henri Becquerel
Marie Curie
Rutherford
Planck
Explanation - Henri Becquerel discovered natural radioactivity in 1896 while working with uranium salts.
Correct answer is: Henri Becquerel
Q.24 Which law explains blackbody radiation?
Planck’s law
Newton’s law
Ohm’s law
Hooke’s law
Explanation - Planck’s law accurately explains blackbody radiation spectrum using quantized energy levels.
Correct answer is: Planck’s law
Q.25 What is the charge of a neutron?
Positive
Negative
Zero
Depends on isotope
Explanation - A neutron is electrically neutral with zero charge.
Correct answer is: Zero