a 6 cm object is placed perpendicular to the principal axis of a convex lens of focal length 25 cm. The distance of the object from the lens is 40 cm. calculate and determine
i)the position of and
ii)the size of the image formed
Answers
INFORMATION GIVEN
The size of the object (O) = 6 cm
The size of image (I) = ?
Distance of the object (u) = 40 cm(negative)
Focal length (f) = 25 cm(positive)
Distance of the image (v) = ?
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WORKING
For convex lens :
u is negative and f is positive
We know that : 1/f = 1/v - 1/u
1/f = 1/v + 1/u [ u is negative ]
==> 1/v = 1/40 + 1/25
==> 1/v = ( 8 +5 ) / 200
==> 1/v = 13 / 200
==> v = 200 / 13....................(1)
==> v = 15.384
==> v = 15.38 cm approx.
(1) The position of the image is 15.38 cm behind the lens.
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We know that : I / O = v / u
since u is negative .
==> I / 6 = 200 / 13 /- 40
==> I / 6 = - 5 / 13
==> I = -30 / 13
==> I = - 2.307
==> I = -2.31 approx.
(2) Image is diminished 2.31 times approx.
Hope it helps you:-)
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Answer:
principal axis of a convex lens of focal length 25 cm. The distance of the object from the lens is 40 cm. calculate and determine
i)the position of and
ii)the size of the image formed
Explanation:
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