Question

A paperweight in the form of a hemisphere of radius 3.0 cm is used to hold down a printed page. An observer looks at the page vertically through the paperweight. At what height above the page will the printed letters near the centre appear to the observer ?

Answer 1

r = 3 cm $u=\frac{3}{2}$

${\mu }_1=9$

$v=9$

$\frac{{\mu }_2}{v}-\frac{{\mu }_1}{u}=\frac{{\mu }_2-{\mu }_1}{r}$

$\Rightarrow \frac{9}{v}-\frac{3}{2\times (-3)}=\frac{1-5}{-3}$

$\Rightarrow \frac{1}{v}+\frac{1}{2}=\frac{1}{6}$

$\Rightarrow \frac{1}{v}=\frac{1}{6}-\frac{1}{2}=\frac{-2}{6}$

$\Rightarrow \frac{1}{v}=\frac{-1}{3}$

$\Rightarrow v=-3$

$\because u=v80$ no shift.