Advertisements
Advertisements
प्रश्न
Distinguish between myopia and hypermetropia. Show diagrammatically how these defects can be corrected.
उत्तर
• Nearsightedness or Myopia − A person suffering from myopia can see only nearby objects clearly, but cannot see the objects beyond a certain distance clearly.
Myopic eye: 
Correction − In order to correct the eye for this defect, a concave lens of suitable focal length is placed close to the eye so that the parallel ray of light from an object at infinity after refraction through the lens appears to come from the far point P'of the myopic eye.
• Farsightedness or Hypermetropia − A person suffering from hypermetropia can see distant objects clearly, but cannot see nearby objects.
Hypermetropic eye:
Correction − To correct this defect, a convex lens of suitable focal length is placed close to the eye so that the rays of light from an object placed at the point N after refraction through the lens appear to come from the near point N'of the hypermetropic eye.
APPEARS IN
संबंधित प्रश्न
An angular magnification (magnifying power) of 30X is desired using an objective of focal length 1.25 cm and an eyepiece of focal length 5 cm. How will you set up the compound microscope?
Draw a ray diagram showing image formation in a compound microscope ?
Suggest two ways by which the resolving power of a microscope can be increased?
Draw a ray diagram showing the image formation by a compound microscope. Hence obtained expression for total magnification when the image is formed at infinity.
A compound microscope forms an inverted image of an object. In which of the following cases it it likely to create difficulties?
Define the magnifying power of a microscope in terms of visual angle.
In the case of a regular prism, in minimum deviation position, the angle made by the refracted ray (inside the prism) with the normal drawn to the refracting surface is ______.
| A compound microscope consists of two converging lenses. One of them, of smaller aperture and smaller focal length, is called objective and the other of slightly larger aperture and slightly larger focal length is called eye-piece. Both lenses are fitted in a tube with an arrangement to vary the distance between them. A tiny object is placed in front of the objective at a distance slightly greater than its focal length. The objective produces the image of the object which acts as an object for the eye-piece. The eye-piece, in turn, produces the final magnified image. |
In a compound microscope, the images formed by the objective and the eye-piece are respectively.
In a compound microscope an object is placed at a distance of 1.5 cm from the objective of focal length 1.25 cm. If the eye-piece has a focal length of 5 cm and the final image is formed at the near point, find the magnifying power of the microscope.
What is meant by a microscope in normal use?
