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A point object O is placed in front of a concave mirror of focal length 10cm. A glass slab of refractive index mu=3//2 and thickness 6cm is inserted between the object and mirror. Q. Find the position and nature of the final image when the distnace x shown in figure, is 20cm. |
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Answer» 17CM, virtual `Deltax=(1-(1)/(mu))t=(1-(2)/(3))(6)=2cm` i.e., for the mirror, the object isplaced at a distanced `(32-Deltax)=30cm` from it. APPLYING mirror formula, `(1)/(v)+(1)/(u)=(1)/(F)` `(1)/(v)+(1)/(30)=-(1)/(10)` or, `v=-15cm` a. when `x=5cm:` The light FALLS on the slab on its return journey as shown. But the slab will again shift it by a distance `Deltax=2cm` . Hence the FINAL real image is formed at a distance `(15+2)=17cm` from the mirror.  b. When `x=20cm:` This time also the final image is at a distance of 17cm from the mirror but it is virtual as shown. BMS_V04_C01_E01_384_S02.png" width="80%"> |
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