Assertion and Reason Questions Chapter-10 Wave Optics
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 behaves as a wave when it passes through a narrow slit.
Reason (R): The wave nature of light causes it to spread out after
passing through a slit.
2. Assertion (A): Young's double-slit experiment demonstrates the interference
of light.
Reason (R): Interference occurs due to the superposition of waves
from two coherent sources.
3. Assertion (A): The condition for constructive interference is that the path
difference between two waves must be an integer multiple of the wavelength.
Reason (R): This condition results in waves reinforcing each other
at points of overlap.
4. Assertion (A): The width of the central maximum in a single-slit diffraction
pattern is larger than that of the subsequent maxima.
Reason (R): The intensity of light decreases as the distance from
the central maximum increases.
5. Assertion (A): The angle of diffraction increases as the width of the slit
decreases.
Reason (R): A narrower slit causes more spreading of the
wavefront.
6. Assertion (A): Diffraction is more pronounced when the size of the obstacle
is comparable to the wavelength of the wave.
Reason (R): The wavefront interacts significantly with obstacles
of similar size, leading to greater bending.
7. Assertion (A): Polarized light has electric field vibrations in a single
plane.
Reason (R): Natural light consists of waves vibrating in multiple
planes.
8. Assertion (A): The intensity of light in an interference pattern is maximum
at points of constructive interference.
Reason (R): Maximum intensity occurs where the waves are in phase.
9. Assertion (A): The fringe width in a double-slit experiment is directly
proportional to the distance between the slits.
Reason (R): Wider slit separation increases the path difference
between light waves.
10. Assertion (A): In a diffraction pattern, the first minimum occurs at an
angle related to the wavelength and slit width.
Reason (R): The first minimum is produced when the path difference
is equal to the wavelength.
11. Assertion (A): Coherent sources of light are essential for producing an
interference pattern.
Reason (R): Coherent sources maintain a constant phase
relationship, allowing for stable interference.
12. Assertion (A): The phenomenon of interference can occur with both light and
sound waves.
Reason (R): Both light and sound exhibit wave properties, allowing
for interference effects.
13. Assertion (A): A diffraction grating produces more distinct patterns than a
double slit.
Reason (R): A diffraction grating has more slits, leading to
better separation of wavelengths.
14. Assertion (A): The critical angle for total internal reflection depends on
the refractive indices of the two media involved.
Reason (R): The critical angle is defined as the angle of
incidence that produces an angle of refraction of 90 degrees.
15. Assertion (A): A lens can produce both real and virtual images.
Reason (R): The type of image formed by a lens depends on the
position of the object relative to the lens's focal point.
16. Assertion (A): Light can be polarized using a polarizing filter.
Reason (R): A polarizing filter allows only light waves vibrating
in a particular direction to pass through.
17. Assertion (A): The fringe width in a double-slit experiment decreases with
increasing distance between the slits.
Reason (R): As the slit distance increases, the path difference
becomes less significant.
18. Assertion (A): Light waves can interfere with each other to produce dark
regions on a screen.
Reason (R): Dark regions are caused by destructive interference of
light waves.
19. Assertion (A): In a single-slit diffraction pattern, the intensity at the
center maximum is greater than at the first minimum.
Reason (R): Intensity decreases as one moves away from the center
of the pattern.
20. Assertion (A): The diffraction pattern of a single slit consists of a
central maximum and several smaller maxima on either side.
Reason (R): The central maximum is wider due to the larger number
of waves contributing to it.
21. Assertion (A): The wavelength of light affects the angle of diffraction in a
single-slit experiment.
Reason (R): Longer wavelengths produce greater angles of
diffraction compared to shorter wavelengths.
22. Assertion (A): The refractive index of a medium is defined as the ratio of
the speed of light in vacuum to the speed of light in the medium.
Reason (R): A higher refractive index indicates that light travels
slower in that medium compared to vacuum.
23. Assertion (A): A converging lens can produce a virtual image.
Reason (R): Virtual images are formed when the object is located
within the focal length of the lens.
24. Assertion (A): The angle of incidence is equal to the angle of reflection
according to the law of reflection.
Reason (R): This law applies to all types of waves, including
light and sound.
25. Assertion (A): Light can exhibit both wave-like and particle-like
properties.
Reason (R): The dual nature of light is a fundamental concept in
quantum mechanics.
26. Assertion (A): The intensity of light decreases with distance from the
source in an interference pattern.
Reason (R): Light spreads out as it moves away from the source,
resulting in reduced intensity.
27. Assertion (A): A convex lens can converge parallel rays of light to a single
point.
Reason (R): The point at which the rays converge is called the
focal point of the lens.
28. Assertion (A): The phenomenon of total internal reflection occurs when light
travels from a denser to a rarer medium.
Reason (R): Total internal reflection can only occur at angles
greater than the critical angle.
29. Assertion (A): The speed of light is constant in a vacuum but varies in
different media.
Reason (R): The refractive index of a medium affects the speed of
light passing through it.
30. Assertion (A): The diffraction pattern of a single slit has a larger central
maximum compared to a double-slit pattern.
Reason (R): The single slit allows more light to interfere
constructively at the center.
31. Assertion (A): Light waves can exhibit polarization by reflection.
Reason (R): When light reflects off a surface, it can become
partially or fully polarized depending on the angle of incidence.
32. Assertion (A): A beam of white light can produce a spectrum when passed
through a prism.
Reason (R): Different wavelengths of light refract at different
angles when passing through a prism.
33. Assertion (A): Diffraction effects are more noticeable for sound waves than
for light waves.
Reason (R): Sound waves have longer wavelengths compared to
visible light.
34. Assertion (A): The fringe width in a double-slit experiment can be
calculated using the formula \(\frac {\lambda D}{d} \).
Reason (R): Here, \(\lambda \) is the wavelength, D is the distance
to the screen, and ddd is the distance between the slits.
35. Assertion (A): The intensity of light at any point in an interference
pattern depends on the phase difference of the waves.
Reason (R): The phase difference determines whether the waves
interfere constructively or destructively.
36. Assertion (A): Diffraction gratings are used to separate different
wavelengths of light effectively.
Reason (R): The large number of slits in a diffraction grating
allows for precise angle measurement of different wavelengths.
37. Assertion (A): The path difference in an interference pattern must be equal
to \(\frac{\lambda}{2}\) for destructive interference to occur.
Reason (R): This condition results in the two waves being out of
phase.
38. Assertion (A): Light can be diffracted even by small obstacles.
Reason (R): The diffraction effect is more pronounced when the
size of the obstacle is close to the wavelength of the light.
39. Assertion (A): A concave mirror can form both real and virtual images.
Reason (R): The type of image depends on the position of the
object relative to the focal point.
40. Assertion (A): The diffraction pattern produced by a single slit is
characterized by a central maximum and multiple minima.
Reason (R): The minima occur due to destructive interference of
light waves.
41. Assertion (A): The phenomenon of interference can occur with sound waves as
well as light waves.
Reason (R): Interference is a general property of all wave
phenomena.
42. Assertion (A): The speed of light in a medium can be calculated using the
refractive index.
Reason (R): The refractive index is the ratio of the speed of
light in vacuum to that in the medium.
43. Assertion (A): White light can be separated into its constituent colors
using a prism.
Reason (R): Different colors of light have different refractive
indices when passing through a prism.
44. Assertion (A): The angular width of the central maximum in a single-slit
diffraction pattern increases with increasing slit width.
Reason (R): A wider slit allows more light to pass through, which
affects the angular width of the central maximum.
45. Assertion (A): Light waves can interfere constructively at certain points in
an interference pattern.
Reason (R): Constructive interference occurs when the path
difference between two waves is an integer multiple of the wavelength.
46. Assertion (A): The intensity of the light at the minima in an interference
pattern is zero.
Reason (R): At the minima, destructive interference occurs due to
the cancellation of waves.
47. Assertion (A): A laser beam can produce a clearer interference pattern than
light from a regular bulb.
Reason (R): Laser light is coherent, while light from a bulb is
incoherent.
48. Assertion (A): The intensity of the central maximum in a double-slit
experiment is greater than the intensity of the first-order maxima.
Reason (R): More waves contribute to the central maximum compared
to the first-order maxima.
49. Assertion (A): The critical angle is a property of a given medium.
Reason (R): The critical angle depends on the refractive indices
of both the medium and the surrounding environment.
50. Assertion (A): Light waves can exhibit diffraction when they pass through
small openings.
Reason (R): The amount of diffraction increases as the size of the
opening decreases relative to the wavelength of light.