Question

A particle lies on the bottom ofa tank T filled with water upto a height of90 cm·The medium above the surface ofwater is ofRI, 2 above which there is mirror M. Beyond M the region contains air ( 1). The distance of the image formed by the mirror after reflection of the rays coming from Piscm w.rt.mirror) 2 610 1-2 yち μ. 1.2 2 23 A) 150 cm B) 120 cm C) 140 cmD)110

Answer 1

the answer to above question is B. 120cm.

it is explained as below:

If a beaker is filled with immiscible transparent liquids of R.I 1, R.I 2, R.I 3.....having respective thickness of the layers t1, t2, t3,......, then the apparent depth of the bottom of beaker is given as t1/R.I 1 + t2/R.I 2 + t3/R.I 3 + .......

so, from above statement t1=90, RI 1 = 4/3=1.33,,, t2=59, RI 2= 1.2,

putting values in above equation we get total depth is equal to 117 cm which can be round of to 120 cm.