Science (English Medium) इयत्ता १२ - CBSE Important Questions for Physics

Draw a labelled ray diagram of a refracting telescope ?

Unpolarised light is incident on a polaroid. How would the intensity of transmitted light change when the polaroid is rotated?

In Young’s double slit experiment using monochromatic light of wavelength λ, the intensity of light at a point on the screen where path difference is λ, is K units. Find out the intensity of light at a point where path difference is λ/3.

Use Huygens’s principle to explain the formation of diffraction pattern due to a single slit illuminated by a monochromatic source of light.

When the width of the slit is made double the original width, how would this affect the size and intensity of the central diffraction band?

A slit of width 0.6 mm is illuminated by a beam of light consisting of two wavelengths 600 nm and 480 nm. The diffraction pattern is observed on a screen 1.0 m from the slit. Find:

1. The distance of the second bright fringe from the central maximum pertaining to the light of 600 nm.
2. The least distance from the central maximum at which bright fringes due to both wavelengths coincide.

The critical angle for a pair of two media A and B of refractive indices 2.0 and 1.0 respectively is:

A ray of light travels from a medium into the water at an angle of incidence of 18°. The refractive index of the medium is more than that of water and the critical angle for the interface between the two media is 20°. Which one of the following figures best represents the correct path of the ray of light?

A point source of light is placed at the bottom of a tank filled with water, of refractive index µ, to a depth d. The area of the surface of water through which light from the source can emerge is:

For which of the following media, with respect to air, the value of critical angle is maximum?

The critical angle of the pair of a medium and air is 30°. The speed of light in the medium is:

In a diffraction pattern due to a single slit, how will the angular width of the central maximum change, if orange light is used in place of green light?

Justify your answer.

In a diffraction pattern due to a single slit, how will the angular width of the central maximum change, if the screen is moved closer to the slit?

Justify your answer.

In a diffraction pattern due to a single slit, how will the angular width of the central maximum change, if the slit width is decreased?

Justify your answer.

• Assertion (A): In Young's double slit experiment all fringes are of equal width.
• Reason (R): The fringe width depends upon the wavelength of light (λ) used, the distance of the screen from the plane of slits (D) and slits separation (d).

What happens to the interference pattern when two coherent sources are infinitely close?

What happens to the interference pattern when two coherent sources are far apart from each other?

In Young's double-slit experiment, the screen is moved away from the plane of the slits. What will be its effect on the following?

1. The angular separation of the fringes.
2. Fringe-width.

Using Huygens's construction, show how a plane wave is reflected from a surface. Hence verify the law of reflection.

A proton and an α-particle have the same de-Broglie wavelength. Determine the ratio of their accelerating potentials