Question

A convex lens magnifies the object 5 times. If the object is displaced 3 cm backward then magnification remains just 2 times find the focal length of the object and the 1st position of the object​

Answer 1

Answer: a concave lens magnifies 5 times. if the object is displaced 3 cm backwards, then, magnification remains just 2 times. find the focal length of lens and first position of object.

Explanation: Mark me as brainliest.

Answer 2

Explanation:

Focal length of the convex lens f=30cm

A convex lens forms a magnified real image when the image is inverted i.e. magnification must be negative.

Magnification of the lens m=−5

Using lens formula

v

1

−

u

1

=

f

1

We get

f

v

=1−m

∴

30

v

=1−(−5)

⟹ v=180cm

Using m=

u

v

(for lens)

∴ −5=

u

180

⟹ u=−36cm

Thus the object distance must be 36cm in front of the lens.