A convex lens of focal length 
and a concave lens of 
focal length are placed so as to have the same axis. If a parallel beam of light falling on convex lens leaves concave lens as a parallel beam, then the distance between two lenses will be
a)
40 
b)
30 
c)
20 
d)
10 
A convex lens of focal length and a concave lens of focal length are placed so as to have the same axis. If a parallel beam of light falling on convex lens leaves concave lens as a parallel beam, then the distance between two lenses will be
a)
40
b)
30
c)
20
d)
10
Question ID - 153026 | SaraNextGen Top Answer
A convex lens of focal length and a concave lens of focal length are placed so as to have the same axis. If a parallel beam of light falling on convex lens leaves concave lens as a parallel beam, then the distance between two lenses will be
a)
40
b)
30
c)
20
d)
10
|
A convex lens of focal length |
|||||||
|
a) |
40 |
b) |
30 |
c) |
20 |
d) |
10 |
1 Answer
127 votes
Answer Key / Explanation : (c) -
|
(c) Let distance between lenses be So by using
|
. As per the given condition, combination behaves as a plane glass plate, having focal length 
127 votes
Answer Link
127