Civil Engineering - Surveying - Discussion
Discussion Forum : Surveying - Section 1 (Q.No. 22)
22.
Two concave lenses of 60 cm focal length are cemented on either side of a convex lens of 15 cm focal length. The focal length of the combination is
Discussion:
38 comments Page 4 of 4.
Saubhagya laxmi said:
1 decade ago
1/60-1/15 = -1/20 then how the answer z 30?
Aswin said:
1 decade ago
How is this calculated? Please explain.
Ravi said:
1 decade ago
1/f = 1/f1+1/f2.
1/60 = 1/15+1/f2.
1/60-1/15 = 1/f2.
1/f2 = 1/30.
f2 = 30.
1/60 = 1/15+1/f2.
1/60-1/15 = 1/f2.
1/f2 = 1/30.
f2 = 30.
(1)
M.lokeswara Rao said:
1 decade ago
1/f = 1/f1+1/f2.
1/60 = 1/15+1/f2.
f2 = 30.
1/60 = 1/15+1/f2.
f2 = 30.
Nitin said:
1 decade ago
1/f = 1/f1 + 1/f2.
1/f = 1/60 + 1/60.
= 1/30. So combination is 30.
1/f = 1/60 + 1/60.
= 1/30. So combination is 30.
Manasa reddy said:
1 decade ago
If we substitute d values in above formula am getting f2=20.
Karan Dumbare said:
1 decade ago
1/f = 1/F1+1/F2.
1/60 = 1/15+1/F2.
F = 30.
1/60 = 1/15+1/F2.
F = 30.
Pawan kumar said:
1 decade ago
1/f = -1/60 -1/60 +1/15 = 1/30/
f = 30.
f = 30.
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