56. Explain magnification in a spherical mirror.
57. Explain the different types of images formed by a concave mirror. ALSO
image in each case
kes formed by a concave mirror. Also give the characteristics of the
58. Give the sign conventions of a spherical mirror in all types of cases
Describe the nature of the image formed when the object is placed at a distance of 20 cm from a
concave mirror of focal length 10 cm.
00. An object 1 cm high is placed on the axis and 15 m from a concave mirror of focal length 10 cm. Find
the position, nature, magnification and size of the image
61. An object placed 20 cm in front of a mirror is found to have an image 15 cm (a) in front of it. (b)
behind it. Find the focal length of the mirror and the kind of mirror in each case.
62. Define refractive index.
63. Why does a diamond sparkle?
64. The speed of light in what is 2.25 x 10 m/s. If the speed of light in vacuum be 3 x 10 m/s, calculate
the refractive index of water.
65. Define Snell's Law of Refraction.
66. Draw a ray diagram to show why a stick half immersed in water appears to be bent at the surface.
67. What is power of a lens?
68. How is the refractive index of an optical medium related to the speed of light in that medium?
69. A 2 cm high candle flame is placed at a distance of 80 cm from a white screen. On placing a convex
lens exactly at the midpoint of the candle and the screen, a distinct image of the flame is seen on the
screen. What is the focal length of the lens and the size of the candle flame image formed? Draw a ray
diagram to show the formation of the image in this case
70. The power of a lens is -4.0 D. what is the nature of this tens?
71. A convex lens has a focal length of 10 cm at what distance from the lens should the object be placed
so that it forms a real and inverted image 20 cm away from the lens? What would be the size of the
image formed is the object is 2 cm high? With the help of a ray diagram show the formation of the
image by the lens in this case.
72. What are the various rules followed by light rays while passing through a lens?
73. Write a short note on the sign convention for lenses.
74. What name is given to the angle of incidence whose corresponding angle of refraction is 90%?
75. Write down the magnification formula for a lens in terms of object distance and image distance. How
does it differ from the corresponding formula for a mirror?
Answers
Answer:
Explanation:Let us do a quick activity. Stand in front of a mirror and mark your position with a colored tape and label it as point A. Now, from point A, walk a little away from the mirror and mark it again with a colored tape and label it as point B. Can you calculate the distance from point A to point B? Need help in solving this problem? This distance can easily be calculated using the mirror formula. Let’s scroll ahead to find more. The sign convention for spherical mirrors follows a set of rules known as the “New Cartesian Sign Convention”, as mentioned below:
a. The pole (p) of the mirror is taken as the origin.
b. The principal axis is taken as the x-axis of our coordinate system.
c. The object is always placed on the left side of the mirror which implies that light falling from the object on the mirror is on the left-hand side.
d. All the distances parallel to the principal axis are measured from the pole (p) of the mirror.
e. All the distances measured from the pole (p) on the right-hand side of the mirror are taken as positive and those on the left-hand side of the mirror are taken as negative.
f. Distances measured perpendicular to and above the principal axis are taken as positive.
g. All the distances below the principal axis are taken as negative.