A convex lens of focal length 20 cm produces images of the same magnification 2 when an object is kept at two distances x1 and x2 (x1>x2) from the lens. The ratio of x1 and x2 is :
(a)
3:1
(b)
2:1
(c)
4:3
(d)
5:3
A convex lens of focal length 20 cm produces images of the same magnification 2 when an object is kept at two distances x1 and x2 (x1>x2) from the lens. The ratio of x1 and x2 is :
(a)
3:1
(b)
2:1
(c)
4:3
(d)
5:3
Question ID - 51288 | SaraNextGen Top Answer
A convex lens of focal length 20 cm produces images of the same magnification 2 when an object is kept at two distances x1 and x2 (x1>x2) from the lens. The ratio of x1 and x2 is :
(a)
3:1
(b)
2:1
(c)
4:3
(d)
5:3
|
A convex lens of focal length 20 cm produces images of the same magnification 2 when an object is kept at two distances x1 and x2 (x1>x2) from the lens. The ratio of x1 and x2 is : |
|||
|
(a) |
3:1 |
(b) |
2:1 |
|
(c) |
4:3 |
(d) |
5:3 |
1 Answer
127 votes
Answer Key / Explanation : (a) -
∴ 
−
= 
∴ v = (±2u)
∴ 
+
= 
⇒ 
= 
∴ u1=30 cm
And 
− 
= 
∴ 
= 
∴ u2=10
∴ 
= 3.
127 votes
Answer Link
127