A glass beaker is placed partially filled with water in a sink it has a mass of 390 gm and an interior volume of `500 cm^(2)` when water starts filling the sink, it is found that if beaker is less than half full it will float but if it is more than half full it remains on the bottom of the sink as the water rises to its rim, what is the density of the material of which the beaker is made?

Answer

`2.79gm//c c`

Explanation

From given condition at half filled it is at the verge of sinking. Let outer volume of beaker is `V`.
`W=B`
`(250+390)g = Vxx1xxg`
`V=640cm^(3)`
volume of material of beaker `=640-500`
`140cm^(3)`
density `=("mass")/("volume")`
density `=(390)/(140)` implies density `=2.79 gm//cm^(3)`