Question

Marbles of diameter 1.4cm are dropped into a cylindrical beaker of diameter 7cm , Containing some water. The number of marbles that should be dropped into the beaker so that the water level increases by 5.6cm is _______

Answer 1

let the initial height be 0
then ,
height after rise in level of water=5.6cm
diameter of cylinder=7 cm
so radius of cylinder=3.5cm
volume of cylinder=πr^2h

diameter of marbles=1.4cm
radius=0.7 cm
volume=4/3πr^3

required no. of marbles =volume of cylinder / volume of marbles
=150.