Chapter 9 – Ray Optics and Optical Instruments
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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?
19
Nov
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? 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? November [...]
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 provides a converging power of about 40dioptre and the least converging power of eye lens behind the cornea is about 20 dioptre. From this rough data, estimate the range of accommodation (i.e., the range of converging power of the eye lens) of a normal eye.
19
Nov
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 provides a converging power of about 40dioptre and the least converging power of eye lens behind the cornea is about 20 dioptre. From this rough data, [...]
You are given prism made of crown glass and flint glass with a wide variety of angles. Suggest a combination of prism which will (i) deviate a pencil of white light without much dispersion. (ii) disperse and displace a pencil of white light without much deviation.
19
Nov
You are given prism made of crown glass and flint glass with a wide variety of angles. Suggest a combination of prism which will (i) deviate a pencil of white light without much dispersion. (ii) disperse and displace a pencil of white light without much deviation. A screen is placed 90 cm from an object. [...]
A screen is placed 90 cm from an object. The image an object on the screen is formed by a convex lens two different locations separated by 20 cm. Determine the focal length of the lens is
19
Nov
A screen is placed 90 cm from an object. The image an object on the screen is formed by a convex lens two different locations separated by 20 cm. Determine the focal length of the lens is A screen is placed 90 cm from an object. The image an object on the screen is formed [...]
A small pin fixed on a table top is viewed from above from a distance of 50cm. By what distance would the pin appear to be raised, if it be viewed from the same point through a 15cm. Thick glass slab held parallel to the table ? μ of glass 1.5 Does the answer depend on location of the slab ?
19
Nov
A small pin fixed on a table top is viewed from above from a distance of 50cm. By what distance would the pin appear to be raised, if it be viewed from the same point through a 15cm. Thick glass slab held parallel to the table ? μ of glass 1.5 Does the answer depend [...]
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A small pin fixed on a table top is viewed from above from a distance of 50cm. By what distance would the pin appear to be raised ,
if it be viewed from the same point through a 15cm. Thick glass slab held parallel to the table ? μ of glass 1.5 Does the answer depend on location of the slab ? ,
a) Determine the effective focal length of the combination of the two lenses of focal length 30cm and -20 cm. if they are placed 8.0cm apart with their principal axes coincident. Does the answer depend on which side of the combination a beam of parallel light is incident? Is the notions of effective focal length of this system useful at all? b) An object 1.5 cm in size is placed on the side of the convex lens in the arrangement a) above. The distance between the object and the convex lens is 40cm. Determine the magnification produced by the two-lens system, and the size of the image.
19
Nov
a) Determine the effective focal length of the combination of the two lenses of focal length 30cm and -20 cm. if they are placed 8.0cm apart with their principal axes coincident. Does the answer depend on which side of the combination a beam of parallel light is incident? Is the notions of effective focal length [...]
(a) Fig. shows a cross-section of a ‘light pipe’ made of a glass fibre of refractive index 1.68. The outer covering of the pipe is made of a material of refractive index 1.44. What is the axis of the pipe for which total reflection inside the pipe take place as shown. (b) What is the answer if there is no outer covering if the pipe ?
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Nov
(a) Fig. shows a cross-section of a ‘light pipe’ made of a glass fibre of refractive index 1.68. The outer covering of the pipe is made of a material of refractive index 1.44. What is the axis of the pipe for which total reflection inside the pipe take place as shown. (b) What is the [...]
Use the mirror equation to deduce that: (a) an object placed between f and 2f of a concave mirror produces a real image beyond 2f. (b) a convex mirror always produces a virtual image independent of the location of the object. (c) the virtual image produced by a convex mirror is always diminished in size and is located between the focus and the pole. (d) an object placed between the pole and focus of a concave mirror produces a virtual and enlarged image.
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Nov
Use the mirror equation to deduce that: (a) an object placed between f and 2f of a concave mirror produces a real image beyond 2f. (b) a convex mirror always produces a virtual image independent of the location of the object. (c) the virtual image produced by a convex mirror is always diminished in size [...]
A compound microscope consists of an objective lens of focal length 2.0cm and an eyepiece of focal length 6.25cm separated by a distance of 15cm. How far from the objective should an object be placed in order to obtain the final image at: (a) the least distance of distinct vision (25cm), and (b) at infinity? What is the magnifying power of the microscope in each case?
19
Nov
A compound microscope consists of an objective lens of focal length 2.0cm and an eyepiece of focal length 6.25cm separated by a distance of 15cm. How far from the objective should an object be placed in order to obtain the final image at: (a) the least distance of distinct vision (25cm), and (b) at infinity? [...]
Between the primary and secondary rainbows, there is a dark band known as Alexander’s dark band. This is because
19
Nov
Between the primary and secondary rainbows, there is a dark band known as Alexander’s dark band. This is because Between the primary and secondary rainbows there is a dark band known as Alexander's dark band. This is because November 19, 2020 Category: Chapter 9 - Ray Optics and Optical Instruments , NCERT Exemplar Class 12 [...]