In a young's double slit experiment, the source is white light. One of the holes is covered by a red filter and another by a blue filter. In this case

Consider the diffraction pattern for a small pinhole. As the size of the hole is increased

Which is not true for the image formed in a plane mirror? The image is 

Refractive index of glass w.r.t. water is 9/8. What is the speed of light in water? Given speed of light in glass is \(2\times 10^{ 8 } \ m/s\) .

An astronomical telescope has a magnifying power of 10. In normal adjustment, distance between the objective and eye piece is 22 cm. The focal length of objective lens is

What is visual angle?

Can we obtain the image formed by a convex mirror on a screen? If not, why?

If the wavelength of incident light on a concave mirror is increased, how will the focal length of the mirror change?

What is the wavelength region of visible spectrum?

The refractive index of diamond is much higher than that of glass. How does a diamond cutter make use of this fact?

A myopic person prefers to remove his spectacles while reading a book. Why?

Why does a soap bubble show beautiful colours, when illuminated by white light?

The 6463\(\mathring { A } H_{ \infty }\) -line emitted by hydrogen in a star is found to be red shifted by 15\(\mathring { A } \). Estimate the speed with which the star is receding from the earth.

A microscope is focused on a dot at the bottom of a beaker. Some oil is poured into the beaker to a height of y cm and it is found necessary to raise the microscope through a vertical distance of x cm to bring the dot again into focus. Express refractive index of oil in terms of x and y

A ray of light passes through an equilateral glass prism, such that the angle of incidence is equal to the angle of emergence. If the angle of emergence is ¾ times the angle of the prism, Calculate the refractive index of the glass prism

The bottom of a container is a 4.0 cm thick glass (n = 1.5) slab. The container contain two immiscible liquids A and B of depths 6.0 cm and 8.0 cm, respectively. what is the apparent position of a scratch on the outer surface of the bottom of the glass slab when viewed through the container? Refractive indices of A  and B are 1.4 and 1.3 respectively.

Let us list some of the factors which could possibly influence the speed of wave propagation:
(i) nature of the source
(ii) direction of propagation
(iii) motion of the source and/or observer 
(iv) wavelength
(v) intensity of the wave.
On which of these factors, if any, does
(a) the speed of light in vacuum
(b) the speed of light in a medium (say glass or water) depend?

(a) Good quality sun-glasses made of polaroids are preferred over ordinary coloured glasses. Justifying your answer.
(b) Two polaroids P₁ and P₂ are placed in crossed positions. A third polaroid P₃ is kept between P₁ and P₂ such that pass axis of P₃ is parallel to that of P₁ How would the intensity of light 10 transmitted through P₂ vary as P₃ is rotated? Draw a plot of intensity '\(\theta\)' Vs the angle 'e', between pass axes of P₁ and P₃.

A beam of white light on passing through a hollow prism gives no spectrum. Why?

(a) A point object is placed in front of a double convex lens (of refractive index n =n₂/n₁ with respect air) with its spherical faces of radii of curvature R₁ and R_2.. Show the path of rays due to surface to obtain the formation of the real image of the object.
Hence obtain the lens maker's formula for a thin lens.
(b) A double convex lens having both faces of the same radius of curvature has refractive index 1.55. Find out the radius of curvature of the lens required to get the focal length of 20 cm.

Show that at polarising angle, the reflected and refracted beams of light are at \({ 90 }^{ \circ }\) to each other.

When an object is placed at a distance of 60 cm from a convex spherical mirror, the magnification produced is 1/2. Where should the object be placed to get a magnification of 1/3?