Lenses and mirrors
A symmetrical biconvex lens of focal length ‘f’ is cut into four identical pieces along its principal axis and perpendicular to the principal axis. The focal length of one of the four pieces is
For this we first cut lens along its principal axis in two equal parts. In this case focal length remains same. hence now focal length of each part is .
After that we cut the each part perpendicular to the lens. In this case focal length of each part becomes double of the original length. which is .
Hence we get four equal parts of focal length each part.
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Related question
The power of a diverging lens is 10D and that of a converging lens is 6D. When these two lenses are placed in contact with each other. The power of their combination will be
Principal axis is the line joining the pole and the:
The focal length of a concave mirror is Where an object be placed so that its image is two times and inverted
Fill in the following blanks with suitable words :
(a) Parallel rays of light are refracted by a convex lens to a point called the ______
(b) The image in a convex lens depends upon the distance of the ____ from the lens.