A converging lens of focal length 15 cm and a converging mirror of focal length 10 cm are placed 50 cm apart. If a pin of length 2.0 cm is placed 30 cm from the lens farther away from the mirror, where will the final image form and what will be the size of the final image ?

Answer

A, B, C

Explanation

Given that `f_1=15cm, F_m=10cm,
`h_0=2cm`
The object is placed 30 cm from lens
`1/v-1/u=1/f`
`rarr v=(uf)/(u+f)`
since `u=-30cm and f=15cm`
`so, v=((-30)x15)/((-30+15))`
`=(-450)/(-15)=30cm`
So, real and inverted image AB will be formed at 30 cm from the lens and it will be of same size as the object. Now this real image is the a distance 20 cm from the concave mirror. Since `f_m=10` this real image is at the center of curvature of the mirror. So the mirror wil form an inverted image A"B" at the same place size. Again due to refractiin in the lens the fiN/Al image will formed at AB and will be of same size as that of object. (A"B")`