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Ashok0210

Asked: March 21, 2021In: Class 12 Physics

What is the focal length of a convex lens of focal length 30 cm in contact with a concave lens of focal length 20 cm? Is the system a converging or a diverging lens? Ignore thickness of the lenses.

Class 12 Physics CBSE and UP Board Ray Optics and Optical Instruments Chapter-9 Exercise 9.10 NCERT Solutions for Class 12 Physics Chapter 9 Question-10

Ashok0210

Asked: March 21, 2021In: Class 12 Physics

An object of size 3.0 cm is placed 14 cm in front of a concave lens of focal length 21 cm. Describe the image produced by the lens. What happens if the object is moved further away from the lens?

Class 12 Physics CBSE and UP Board Ray Optics and Optical Instruments Chapter-9 Exercise 9.9 NCERT Solutions for Class 12 Physics Chapter 9 Question-9

Ashok0210

Asked: March 21, 2021In: Class 12 Physics

A beam of light converges at a point P. Now a lens is placed in the path of the convergent beam 12 cm from P. At what point does the beam converge if the lens is (a) a convex lens of focal length 20 cm, and (b) a concave lens of focal length 16 cm?

Class 12 Physics CBSE and UP Board Ray Optics and Optical Instruments Chapter-9 Exercise 9.8 NCERT Solutions for Class 12 Physics Chapter 9 Question-8

Ashok0210

Asked: March 21, 2021In: Class 12 Physics

Double-convex lenses are to be manufactured from a glass of refractive index 1.55, with both faces of the same radius of curvature. What is the radius of curvature required if the focal length is to be 20 cm?

Class 12 Physics CBSE and UP Board Ray Optics and Optical Instruments Chapter-9 Exercise 9.7 NCERT Solutions for Class 12 Physics Chapter 9 Question-7

Ashok0210

Asked: March 21, 2021In: Class 12 Physics

A man with normal near point (25 cm) reads a book with small print using a magnifying glass: a thin convex lens of focal length 5 cm. (a) What is the closest and the farthest distance at which he should keep the lens from the page so that he can read the book when viewing through the magnifying glass? (b) What is the maximum and the minimum angular magnification (magnifying power) possible using the above simple microscope?

Class 12 Physics CBSE and UP Board Ray Optics and Optical Instruments Chapter-9 Exercise 9.28 NCERT Solutions for Class 12 Physics Chapter 9 Question-28

Ashok0210

Asked: March 21, 2021In: Class 12 Physics

A person looking at a person wearing a shirt with a pattern comprising vertical and horizontal lines is able to see the vertical lines more distinctly than the horizontal ones. What is this defect due to? How is such a defect of vision corrected?

Class 12 Physics CBSE and UP Board Ray Optics and Optical Instruments Chapter-9 Exercise 9.27 NCERT Solutions for Class 12 Physics Chapter 9 Question-27

Ashok0210

Asked: March 21, 2021In: Class 12 Physics

A myopic person has been using spectacles of power -1.0 dioptre for distant vision. During old age he also needs to use separate reading glass of power + 2.0 dioptres. Explain what may have happened.

Class 12 Physics CBSE and UP Board Ray Optics and Optical Instruments Chapter-9 Exercise 9.26 NCERT Solutions for Class 12 Physics Chapter 9 Question-26

Ashok0210

Asked: March 21, 2021In: Class 12 Physics

Does short-sightedness (myopia) or long-sightedness (hypermetropia) imply necessarily that the eye has partially lost its ability of accommodation? If not, what might cause these defects of vision?

Class 12 Physics CBSE and UP Board Ray Optics and Optical Instruments Chapter-9 Exercise 9.25 NCERT Solutions for Class 12 Physics Chapter 9 Question-25

Ashok0210

Asked: March 21, 2021In: Class 12 Physics

For a normal eye, the far point is at infinity and the near point of distinct vision is about 25cm in front of the eye. The cornea of the eye provides a converging power of about 40 dioptres, and the least converging power of the eye-lens behind the cornea is about 20 dioptres. From this rough data estimate the range of accommodation (i.e., the range of converging power of the eye-lens) of a normal eye.

Class 12 Physics CBSE and UP Board Ray Optics and Optical Instruments Chapter-9 Exercise 9.24 NCERT Solutions for Class 12 Physics Chapter 9 Question-24

Ashok0210

Asked: March 21, 2021In: Class 12 Physics

You are given prisms made of crown glass and flint glass with a wide variety of angles. Suggest a combination of prisms which will (a) deviate a pencil of white light without much dispersion, (b) disperse (and displace) a pencil of white light without much deviation.

Class 12 Physics CBSE and UP Board Ray Optics and Optical Instruments Chapter-9 Exercise 9.23 NCERT Solutions for Class 12 Physics Chapter 9 Question-23

What is the focal length of a convex lens of focal length 30 cm in contact with a concave lens of focal length 20 cm? Is the system a converging or a diverging lens? Ignore thickness of the lenses.

An object of size 3.0 cm is placed 14 cm in front of a concave lens of focal length 21 cm. Describe the image produced by the lens. What happens if the object is moved further away from the lens?

A beam of light converges at a point P. Now a lens is placed in the path of the convergent beam 12 cm from P. At what point does the beam converge if the lens is (a) a convex lens of focal length 20 cm, and (b) a concave lens of focal length 16 cm?

Double-convex lenses are to be manufactured from a glass of refractive index 1.55, with both faces of the same radius of curvature. What is the radius of curvature required if the focal length is to be 20 cm?

A person looking at a person wearing a shirt with a pattern comprising vertical and horizontal lines is able to see the vertical lines more distinctly than the horizontal ones. What is this defect due to? How is such a defect of vision corrected?

A myopic person has been using spectacles of power -1.0 dioptre for distant vision. During old age he also needs to use separate reading glass of power + 2.0 dioptres. Explain what may have happened.

Does short-sightedness (myopia) or long-sightedness (hypermetropia) imply necessarily that the eye has partially lost its ability of accommodation? If not, what might cause these defects of vision?

You are given prisms made of crown glass and flint glass with a wide variety of angles. Suggest a combination of prisms which will (a) deviate a pencil of white light without much dispersion, (b) disperse (and displace) a pencil of white light without much deviation.

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