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A linear object of size 1.5 cm is placed...

A linear object of size `1.5 cm` is placed at 10 cm from a lens of focal length 20 cm. The optic centre of lens and the object are displaced are displaced a distance `Delta`. Thed magnification of the image formed is m. (Take optic centre of origin). The coordinates of image of A and B are `(x_(1),y_(1))` and `(x_(2),y_(2))` respectively then

A

`(x_(1),y_(1)) = (-20 cm, -2 cm)`

B

`(x_(2),y_(2)) = (-20 cm, 2 cm)`

C

`m = 5`

D

`m = 4`

Text Solution

Verified by Experts

The correct Answer is:
B
`u = - 0 cm , f = 20 cm `

`1/v - 1/u = 1/f , 1/v = 1/20 - 1/10 = (-1)/(20) rArr v = - 20 cm`
Magnification, `m = (v)/(u) = (-20)/(-10) = 2`
Height of image `= 1.5 xx 2 = 3 cm`
The `y_(1)` coordinate of a point A on the image will be
` y_(1) = (-0.5) xx 2 = - 1 cm`
The `y_(2)` coordinate of a point B on the image will be
`y_(2) = 1 xx 2 = 2 cm`
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