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प्रश्न
Write the new Cartesian sign convention for spherical lenses.
State and explain the New Cartesian Sign Convention for spherical lenses.
उत्तर
New Cartesian Sign Convention for spherical lenses:
New Cartesian Sign Convention is used for measuring various distances in the ray diagrams of lenses.
According to this convention:
- Object is always placed on the left of the lens; i.e., light must fall on the lens from left to right.
- All distances parallel to the principal axis are measured from the optical centre of the lens.
- The distances along the direction of incident rays (along the positive x-axis) are taken as positive, whereas the distances opposite to the direction of incident rays (along the negative x-axis) are taken as negative.
- Distances measured above the principal axis (along the positive y-axis) are taken as positive.
- Distances measured below the principal axis (along the negative y-axis) are taken as negative.
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संबंधित प्रश्न
Suppose you have focused on a screen the image of candle flame placed at the farthest end of the laboratory table using a convex lens. If your teacher suggests you to focus the parallel rays of the sun, reaching your laboratory table, on the same screen, what you are expected to do is to move the:
(a) lens slightly towards the screen
(b) lens slightly away from the screen
(c) lens slightly towards the sun
(d) lens and screen both towards the sun
A concave lens always forms a virtual image.
A real image cannot be obtained on a screen.
State two differences between a convex and a concave lens.
Which type of lens forms always a virtual image?
A diverging mirror of radius of curvature 40 cm forms an image which is half the height of the object. Find the object and image positions.
If a spherical lens has a power of, −0.25 D, the focal length of this lens will be :
(a) −4 cm
(b) −400 mm
(c) −4 m
(d) −40 cm
Complete the ray diagram to show how the rays pass into and out of the lens?
Which diagram shows image formation of an object on a screen by a converging lens?
Complete the following table for convex lens:
| Sr. No. | Position of the object | Position of the image | Nature of the image |
| 1. | Beyond 2F1 | __________________ | ________________________ |
| 2. | __________________ | At infinity | ________________________ |
| 3. | __________________ | __________________ | Real, inverted and enlarged |
