Image by mirror formed at 30 cm from mirror at its right and finally by the combination it is formed at 20 cm on right lens.so in air medium magnification by less is unity.In second medium μ=
7
6
,focal length of the lens is given by
1
10
1
f
=
(15−1)(
1
R1
−
1
R2
)
((
15
7
6
−1)(
1
R1
−
1
R2
))
⇒f=
35
2
cm
so in Second medium final image is formed at 140 cm to the right the lens .Second medium does not change the magnification by mirror.So |