MEDIUM
12th West Bengal Board
IMPORTANT
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An air bubble is formed inside water. Does it act as a converging or diverging lens?

Important Questions on Refraction at Spherical Surfaces and Spherical Lens

MEDIUM
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 14 - Refraction at Spherical Surfaces and Spherical Lens>EXERCISE 14>Q 44
A double convex lens is cut into two equal parts by a plane perpendicular to principal axis. If the power of the original lens was 4 D what would be the power of the parts?
HARD
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 14 - Refraction at Spherical Surfaces and Spherical Lens>EXERCISE 14>Q 1
Trace the rays of light showing the formation of an image due to a point object placed on the axis of a spherical surface separating the two media of refractive index n1 and n2. Establish the relation between the distances of the object, the image and the radius of curvature R
HARD
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 14 - Refraction at Spherical Surfaces and Spherical Lens>EXERCISE 14>Q 2
Using the relation for refraction at a single spherical refracting surface, derive the lens' maker's formula.
MEDIUM
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 14 - Refraction at Spherical Surfaces and Spherical Lens>EXERCISE 14>Q 3

Obtain the lens makers formula using the expression n2v-n1u=n2-n1R Here the ray of light propagating from a rarer medium of refractive index n1 to a denser medium of refractive index n2 is incident on the convex side of spherical refracting surface of radius of curvature R.

HARD
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 14 - Refraction at Spherical Surfaces and Spherical Lens>EXERCISE 14>Q 4
Draw a ray diagram to show the formation of the image of an object placed on the axis of a convex refractive surface, of radius of curvature R, separating the two media of refracting indices n1 and n2n2>n1 use this diagram to deduce the relation n2v-n1u=n2-n1R where u and v represent respectively the distances of the object and image formed.
EASY
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 14 - Refraction at Spherical Surfaces and Spherical Lens>EXERCISE 14>Q 5
Define the power of lens. Write its S.I. unit. Two thin convex lenses of focal lengths f1 and f2 are placed in contact coaxially.Derive the expression for the effective focal length of the combination.
HARD
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 14 - Refraction at Spherical Surfaces and Spherical Lens>EXERCISE 14>Q 6
A thin lens, having two surfaces of radii of curvature r1 and r2, made from a material of refractive index μ2, is kept in a medium of refractive index μ1. Derive the Lens maker's formula for this 'set-up'.
MEDIUM
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 14 - Refraction at Spherical Surfaces and Spherical Lens>EXERCISE 14>Q 7
A convex lens is placed over a plane mirror. A pin is now positioned so that there is no parallax between the pin and its image formed by this lens mirror combination. How can this observation be used to find the focal length of the convex lens? Give appropriate reasons in support of your answer.