Optics Answers

why does clear sky look blue?

Two plane parallel plates having thickness of 3cm and 5cm and refractive indices of 1.5 and 1.8 respectively are piled together .A light beam incident on the first plate at an angle of 60' to the normal ,passes through the plates and emerges at the same angle .Find the displacement of the beam.

The path difference between two wavefronts generated by coherent source is 2.1 micron.If the phase difference between these wavefronts at a point is 7.692π,the wavelength of light emitted from the source will be: a)5386Å b)5400Å c)5460Å d)5892Å.

When light of wavelength 5000Å is used in the single slit diffraction experiment,the first diffraction minima is formed at the position θ. If the width of the slit is 10^-4 cm,the magnitude of θ is: a)30 b)45 c)60 d)15.

An object is placed 12cm from a converging lens. An image of the object is formed 12cm from the second focus on the other side of the lens. Calculate the focal length.

Choose the correct statement regarding a double slit experiment.
If the light wavelength becomes shorter, then the interference fringes move closer together.
If the light wavelength becomes longer, then the interference fringes move closer together.
If the slit distance is decreased, then the interference fringes move closer together.
If the slit distance is increased, then the interference fringes move further apart.
If the light wavelength becomes shorter, then the interference fringes move further apart.

Consider the three waves represented by y1=3sin (kx-wt), y2=3sin (kx-wt+2pi/3), y3=3sin (kx-wt+4pi/3)
then the amplitude of resultant of waves at x=0

1 An object is 10 cm in front of a concave mirror of radius 30cm. Describe its image.
2 How far should an object be from a concave mirror of radius 30cm to form a real image 1/6 of its size
3 An object placed in front of a convex mirror of radius 20cm produces an erect image which is one-fifth the size of the object. How far is the object from the mirror
4 The focal length of a curved mirror is --- the radius of the spherical surface
5 What is the difference between a real and a virtual image
6 The image of a child standing in front of a flat mirror is
7 The image formed by a bathroom mirror is
8 An object placed in front of a concave mirror of radius 20 cm produces an inverted image which is one-fifth the size of the object. How far is the object from the mirror
9 What is the the focal length of a convex mirror which produces an image 1/5 the size of an object located 17 cm from the mirror
13 What image is formed when an object is placed between the focal point and the centre of curvature of a concave mirro

Two coherent sources have intensities in the ratio 64:1. The amplitudes are in ratio

an object is placed 60 cm from a spherical convex mirror. If the mirror forms a virtual image 20cm from the mirror what is the magnitude of the mirror's radius of curvature?