List of top Physics Questions on Wave Optics asked in CBSE CLASS XII

In a Young's double-slit experiment, two waves each of intensity I superpose each other and produce an interference pattern. Prove that the resultant intensities at maxima and minima are 4I and zero respectively.
Assertion : In Young’s double-slit experiment, the fringe width for dark and bright fringes is the same. Reason (R): Fringe width is given by \( \beta = \frac{\lambda D}{d} \), where symbols have their usual meanings.
A ray of light MN is incident normally on the face corresponding with side AB of a prism with an isosceles right-angled triangular base ABC. Trace the path of the ray as it passes through the prism when the refractive index of the prism material is \( \sqrt{2} \), and \( \sqrt{3} \).
When monochromatic light is incident on a surface separating two media, the refracted and reflected light both have the same frequency as the incident frequency but the wavelength of refracted light is different. Explain why.

Two slits 0.1 mm apart are arranged 1.20 m from a screen. Light of wavelength 600 nm from a distant source is incident on the slits. How far apart will adjacent bright interference fringes be on the screen? 

The ratio of the intensities at maxima to minima in Young’s double-slit experiment is \( 25 : 9 \). Calculate the ratio of intensities of the interfering waves.

Assertion : Out of Infrared and radio waves, the radio waves show more diffraction effect.

Reason (R): Radio waves have greater frequency than infrared waves.

In a Young’s double-slit experiment, the intensity at the central maximum in the interference pattern on the screen is \( I_0 \). Find the intensity at a point on the screen where the path difference between the interfering waves is \( \frac{\lambda}{6} \).
Define a wavefront. An incident plane wave falls on a convex lens and gets refracted through it. Draw a diagram to show the incident and refracted wavefront.
In a diffraction experiment, the slit is illuminated by light of wavelength 600 nm. The first minimum of the pattern falls at \( \theta = 30^\circ \). Calculate the width of the slit.
Two slits 0.1 mm apart are arranged 1.20 m from a screen. Light of wavelength 600 nm from a distant source is incident on the slits.
Find the angular width (in degrees) of the first bright fringe.

Show the refraction of light wave at a plane interface using Huygens' principle and prove Snell's law.

Write two differences in the patterns of double-slit interference experiment and single-slit diffraction experiment. Light waves from two pinholes illuminated by two sodium lamps do not produce interference patterns. Explain why.
Lights from two independent sources are not coherent. Explain.
What are coherent sources? Why are they necessary for observing a sustained interference pattern?
In the figure, a ray of light is incident on a transparent liquid contained in a thin glass box at an angle of 45° with its one face. The emergent ray passes along the face AB. Find the refractive index of the liquid.
a ray of light is incident on a transparent liquid contained in a thin glass box
The number of peaks of the interference fringes formed within the central peak of the envelope of the diffraction pattern will be:
Draw an intensity distribution graph in case of a double-slit interference pattern.
A beam of light consisting of a known wavelength 520nm and an unknown wavelength λ, used in Young’s double slit experiment, produces two interference patterns such that the fourth bright fringe of unknown wavelength coincides with the fifth bright fringe of known wavelength. Find the value of λ
In a Young’s double slit experiment, the slits are separated by 0.30 mm and the screen is kept 1.5 m away. The wavelength of light used is 600 nm. Calculate the distance between the central bright fringe and the 4thx dark fringe.
A plane light wave propagating from a rarer into a denser medium, is incident at an angle \( i \) on the surface separating two media. Using Huygen’s principle, draw the refracted wave and hence verify Snell’s law of refraction.
Discuss four main causes of energy loss in a real transformer.
Assertion (A): In a Young's double-slit experiment, interference pattern is not observed when two coherent sources are infinitely close to each other. % Reason (R) Reason (R): The fringe width is proportional to the separation between the two sources.
A Young’s double-slit experimental setup is kept in a medium of refractive index \( \frac{4}{3} \). Which maximum in this case will coincide with the 6th maximum obtained if the medium is replaced by air?
In Young’s double slit experiment, find the ratio of intensities at two points on a screen when waves emanating from two slits reaching these points have path differences (i) \(\frac{\lambda}{6}\) and (ii) \(\frac{\lambda}{12}\).