Assertion and Reason Questions Chapter-11 Dual Nature of Radiation and Matter
Assertion (A) and other labelled Reason (R). Select the correct answer to these
questions from the options as given below.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, but R is not the correct explanation of A.
C. A is true, but R is false.
D. A is false, but R is true.
1. Assertion (A): Light exhibits both wave-like and particle-like properties.
Reason (R): The wave-particle duality of light is a fundamental
concept in quantum mechanics.
2. Assertion (A): The photoelectric effect provides evidence for the particle
nature of light.
Reason (R): The photoelectric effect demonstrates that light can
eject electrons from a material surface when it has sufficient energy.
3. Assertion (A): The de Broglie wavelength of an electron is shorter than that
of a photon of the same energy.
Reason (R): Photons have zero rest mass, while electrons have a
non-zero rest mass.
4. Assertion (A): An electron microscope uses the wave nature of electrons to
achieve higher resolution than light microscopes.
Reason (R): Electrons have a smaller wavelength compared to
visible light.
5. Assertion (A): The energy of a photon is directly proportional to its
frequency.
Reason (R): This relationship is expressed by Planck’s equation, E
= hf.
6. Assertion (A): The photoelectric effect cannot occur below a certain
threshold frequency.
Reason (R): Photons below this frequency do not have enough energy
to eject electrons.
7. Assertion (A): Matter waves are associated with all particles, including
macroscopic objects.
Reason (R): The de Broglie wavelength of macroscopic objects is
negligible compared to quantum effects.
8. Assertion (A): The wave function of a particle describes its position and
momentum simultaneously.
Reason (R): The Heisenberg Uncertainty Principle states that
position and momentum cannot be precisely determined at the same time.
9. Assertion (A): The photoelectric effect can be explained using classical wave
theory.
Reason (R): Classical wave theory predicts that the energy of
light increases with intensity.
10. Assertion (A): Wave-particle duality is a characteristic feature of both
light and matter.
Reason (R): Both light and matter exhibit diffraction and
interference patterns.
11. Assertion (A): Increasing the intensity of light increases the energy of the
ejected electrons in the photoelectric effect.
Reason (R): Intensity is related to the number of photons hitting
the surface, not their energy.
12. Assertion (A): The Compton effect demonstrates the particle nature of
X-rays.
Reason (R): The scattering of X-rays can be explained by treating
them as particles colliding with electrons.
13. Assertion (A): Electrons exhibit both quantized energy levels and wave-like
behavior in atoms.
Reason (R): Electrons can be described using quantum mechanics and
wave functions.
14. Assertion (A): Photons can be described as having both energy and momentum.
Reason (R): Photons have zero mass, so they do not have momentum.
15. Assertion (A): The wave nature of matter is significant at macroscopic
scales.
Reason (R): The de Broglie wavelength increases with mass and
decreases with velocity.
16. Assertion (A): In a double-slit experiment, electrons can produce an
interference pattern.
Reason (R): The wave nature of electrons allows them to interfere
with themselves.
17. Assertion (A): The uncertainty principle limits the precision of measuring a
particle's position and momentum.
Reason (R): This principle is a fundamental aspect of quantum
mechanics.
18. Assertion (A): Electrons in an atom can only exist in certain discrete
energy levels.
Reason (R): The quantization of energy levels is a result of
wave-like behavior of electrons.
19. Assertion (A): The wave function of a particle provides information about
its exact position.
Reason (R): The square of the wave function gives the probability
density of finding a particle in a specific region.
20. Assertion (A): Photons can be created or annihilated in pairs during certain
interactions.
Reason (R): Conservation laws, including energy and momentum,
allow this phenomenon.
21. Assertion (A): Wave-particle duality implies that particles can behave as
waves under certain conditions.
Reason (R): The wave nature of particles is evident in diffraction
and interference experiments.
22. Assertion (A): The de Broglie wavelength of an object is inversely
proportional to its momentum.
Reason (R): The formula for de Broglie wavelength is λ = h/p.
23. Assertion (A): The energy of a photon is constant for a given frequency.
Reason (R): Planck's constant relates energy to frequency through
the equation E = hf.
24. Assertion (A): The work function of a material is the minimum energy
required to remove an electron from the surface.
Reason (R): The work function varies with the type of material.
25. Assertion (A): Electrons can only occupy specific orbitals in an atom.
Reason (R): This is due to the quantization of angular momentum in
quantum mechanics.
26. Assertion (A): The frequency of emitted electrons increases with the
intensity of the incident light in the photoelectric effect.
Reason (R): Intensity is related to the energy of each photon.
27. Assertion (A): Light can exhibit interference patterns even when photons are
sent one at a time.
Reason (R): Each photon interferes with itself, demonstrating its
wave nature.
28. Assertion (A): A particle’s momentum can be determined with absolute
precision.
Reason (R): The Heisenberg Uncertainty Principle states there is a
limit to how precisely we can measure both position and momentum.
29. Assertion (A): The wave-particle duality of electrons has been confirmed by
various experiments.
Reason (R): Electrons demonstrate both diffraction and
interference patterns.
30. Assertion (A): The photoelectric effect cannot occur with infrared light.
Reason (R): Infrared light has a lower frequency than visible
light.
31. Assertion (A): The momentum of a photon can be calculated using its
wavelength.
Reason (R): The momentum of a photon is given by the relation p =
h/λ.
32. Assertion (A): The energy of electrons in an atom is quantized.
Reason (R): This quantization arises from the wave nature of
electrons confined in potential wells.
33. Assertion (A): Classical mechanics can accurately describe the behavior of
electrons in atoms.
Reason (R): Electrons behave like particles in well-defined orbits
around the nucleus.
34. Assertion (A): The Compton effect demonstrates the wave nature of X-rays.
Reason (R): The scattering of X-rays can be modeled using wave
properties.
35. Assertion (A): Electromagnetic radiation can behave like a stream of
particles.
Reason (R): Photons are considered the particles of light with
quantized energy.
36. Assertion (A): The intensity of light affects the kinetic energy of emitted
electrons in the photoelectric effect.
Reason (R): Kinetic energy is dependent on the energy of
individual photons.
37. Assertion (A): The dual nature of radiation implies that light can travel
through a vacuum.
Reason (R): Both waves and particles can propagate in a vacuum.
38. Assertion (A): Quantum mechanics is necessary to describe the behavior of
very small particles like electrons.
Reason (R): Classical physics fails to explain phenomena such as
electron diffraction.
39. Assertion (A): An electron's wave function can be used to predict its exact
location.
Reason (R): The wave function provides a probability distribution
of finding the electron.
40. Assertion (A): The threshold frequency is constant for all materials.
Reason (R): Different materials have different work functions,
affecting their threshold frequencies.
41. Assertion (A): X-rays can cause photoelectric emission in materials.
Reason (R): X-rays have energy greater than the work function of
many materials.
42. Assertion (A): Electrons in higher energy states are more stable than those
in lower energy states.
Reason (R): Higher energy states are closer to the nucleus, which
provides stronger binding.
43. Assertion (A): The photoelectric effect demonstrates the particle nature of
light.
Reason (R): Photons must have sufficient energy to liberate
electrons from a material.
44. Assertion (A): A photon can be described as a wave packet.
Reason (R): The wave packet model accounts for the particle-like
behavior of photons.
45. Assertion (A): The photoelectric effect is a phenomenon that can only be
observed with visible light.
Reason (R): The energy of visible light photons is sufficient to
overcome the work function of many materials.
46. Assertion (A): The wave-particle duality is a fundamental concept in quantum
mechanics.
Reason (R): This concept explains various phenomena such as
diffraction, interference, and the photoelectric effect.
47. Assertion (A): The de Broglie hypothesis applies to all types of particles,
including macroscopic objects.
Reason (R): The wavelength associated with large objects is
practically negligible.
48. Assertion (A): The uncertainty principle limits the precision of
measurements of position and momentum simultaneously.
Reason (R): This principle is a fundamental aspect of quantum
mechanics.
49. Assertion (A): The energy levels of an electron in a hydrogen atom are
quantized.
Reason (R): Quantization arises from the wave nature of electrons
in bound states.
50. Assertion (A): The concept of wave-particle duality is essential for
understanding modern physics.
Reason (R): It reconciles the behaviors of light and matter at
quantum scales.