b
(b)If the level in narrow tube goes down by \(h_1\) then in wider tube goes up to \(h_2,\)
Now, \(\pi {r^2}{h_1} = \pi {(nr)^2}{h_2}\)==> \({h_1} = {n^2}{h_2}\)
Now, pressure at point A = pressure at point B
\(h\rho g = ({h_1} + {h_2})\rho 'g\)
==> \( h = \) \(({n^2}{h_2} + {h_2})sg\) \(\left( {{\rm{As}}\;s = \frac{{\rho '}}{\rho }} \right)\) ==> \({h_2} = \frac{h}{{({n^2} + 1)s}}\)
