1.

When an object is moved along the principle axis of a concave mirror placedin air, the image coincides with the object if the object is 50 cm from the mirror. If the mirror is placed at a depth of 20 cm in a transparent medium, the image coincides with the object when the object is 40 cm from the mirror. The refractive index of the liquid is

Answer»

`(5)/(4)`
`(4)/(3)`
`(3)/(2)`
`(5)/(3)`

SOLUTION :According to the question, an object is placed on the principle axis of a CONCAVE mirrot is SHOWN in the figure below,

Since, it is given that, an object at 50 cm from pole is act like, it placed at 40 cm from the pole when mirror is placed inside a transparent medium.
`rArr v_("real") = 50 cm` and `v_("apparent") = 40 cm`
Now, distance outside the transparent medium, `D_("real") = v_("real")` - thickness of transparent medium,
`D_("real") = 50 cm - 20 cm = 30 cm`
Similarly, `D_("apparent") = (40 - 20) cm = 20 cm`
Hence, the refractive index of the LIQUID,
`mu = (D_("ACTUAL"))/(D_("apparent")) = (30)/(20) = (3)/(2)`
`:.` Hence, the correct option is (C ).


Discussion

No Comment Found

Related InterviewSolutions