MEDIUM
12th West Bengal Board
IMPORTANT
Earn 100

A double convex lens has a focal length of 25 cm in air. When it is placed in a liquid of r. i. 4/3 its focal length increases to 75 cm. The r. i. of the material of the lens is

50% studentsanswered this correctly

Important Questions on Refraction at Spherical Surfaces and Spherical Lens

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
A concave lens of f=1 metre produces an image 1/n times the size of the object. The distance in metre of the object from the lens is
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 6
A double convex lens has two surfaces of equal radii R, and refractive index m=1.5. We have
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 7
A convex lens forms a real image of a point object placed on its principal axis. If the upper half of the lens is painted black.
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 8
The distance between an object and a concave lens is m times the focal length of the lens. The linear magnification produced by the lens is
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 9
A thin converging lens of focal length 25 cm forms the image of an object at a distance of 50 cm from the lens. The screen is then drawn closer by a distance of 15 cm. By what distance should the object be shifted so that the image on the screen is sharp again.
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 10
Two lenses of focal lengths f1 and f2 are cemented together and found to possess zero power. Which one of the following is true?
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 11

Two lenses of focal lengths f1 and f2 are cemented together. The equivalent focal length of the combination is

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 12
The distance between the object and a screen is x. If a lens is kept at two positions between them, an image is formed in each case on the screen. The distance between the two positions of the lens is d. The ratio of the sizes of two images is