A cylindrical vessel, whose diameter and height both are equal to 30 cm, is placed on a horizontal surface and a small particle P is placed in it at a distance of 5.0 cm from the centre. An eye is placed at a position such that the edge of the bottom is just visible (see figure 18-E8). The particle P is in the plane of drawing. Up to what minimum height should water be poured in the vessel to make the particle P visible ?

Answer

B, C

Explanation

`tantheta_1=1=30/30`
`theta_1=45^@` ,brgt `In `/_\ Tus` tan45^@(30-4)/(TS)`
`TS=30-4`TS=VR
Pv=20-vR=h-10`
`sintheta_1=(h-10)/(sqrt(h-10)^2+h^2)`
`sintheta_2xxmu_1=mu_1sintheta_1`
or `(h-10)/(sqrt(h-10)^2+h^2)xx43=1xx1/v^2`
`or ((uv_2)(n-10))^2=(sqrt(h-10)^2+h^2)3)^2`
or `32(h-10)^2=9(h-10)^2+h^2`
`or 23(h-10)^2=9h^2`
`or, ((h-10)^2/h)^2-9/23`
`or (h-10)/h=3/4.8`
or `1-10/h3/4.8`
or `10/h=1.8/4.8`
`:. h=(48xx10)/1.8=26.6cm`