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

Find the intensity at a point on a screen in Young's double slit experiment where the interfering waves have a path difference of (i) λ/6, and (ii) λ/2. 

Draw the intensity distribution for the fringes produced in interference ?

Draw the intensity distribution for the diffraction bands produced due to single slit ?

Distinguish between polarized and unpolarized light. Does the intensity of polarized light emitted by a polaroid depend on its orientation? Explain briefly.
The vibration in a beam of polarized light make an angle of 60° with the axis of the polaroid sheet. What percentage of light is transmitted through the sheet?

State the essential conditions for diffraction of light ?

(i) State the essential conditions for diffraction of light.
(ii) Explain diffraction of light due to a narrow single slit and the formation of pattern of fringes on the screen.
(iii) Find the relation for width of central maximum in terms of wavelength 'λ', width of slit 'a', and separation between slit and screen 'D'.
(iv) If the width of the slit is made double the original width, how does it affect the size and intensity of the central band?

Draw a labelled schematic ray diagram of astronomical telescope in normal adjustment.

Which two aberrations do objectives of refracting telescope suffer from? How are these overcome in reflecting telescope?

How does the resolving power of a telescope change on increasing the aperture of the objective lens? Justify your answer.

How does the refractive index of a transparent medium depend on the wavelength of incident light used ?

Why cannot two independent monochromatic sources produce sustained interference pattern?
Deduce, with the help of Young's arrangement to produce interference pattern, an expression for the fringe width.

Monochromatic light of frequency 5.0 × 10¹⁴ Hz is produced by a laser. The power emitted is 3.0 × 10^–3 W. Estimate the number of photons emitted per second on an average by the source ?

A partially plane polarised beam of light is passed through a polaroid. Show graphically the variation of the transmitted light intensity with angle of rotation of the polaroid ?

Explain with the help of a diagram how sunlight is polarised by scattering through atmospheric particles ?

A parallel beam of light of wavelength 500 nm falls on a narrow slit and the resulting diffraction pattern is observed on a screen 1 m away. It is observed that the first minimum is a distance of 2.5 mm away from the centre. Find the width of the slit.

What does a polaroid consist of? How does it produce a linearly polarised light?

Explain briefly how sunlight is polarised by scattering through atmospheric particles.

Write two characteristics features distinguish the diffractions pattern from the interference fringes obtained in Young’s double slit experiment.

Two wavelengths of sodium light 590 nm and 596 nm are used, in turn, to study the diffraction taking place due to a single slit of aperture 1 × 10⁻⁴ m. The distance between the slit and the screen is 1.8 m. Calculate the separation between the positions of the first maxima of the diffraction pattern obtained in the two cases.

A parallel beam of light of 450 nm falls on a narrow slit and the resulting diffraction pattern is observed on a screen 1.5 m away. It is observed that the first minimum is at a distance of 3 mm from the centre of the screen. Calculate the width of the slit.