Question

A uniform pencil floats with 8cm of it's length immersed in water. What length is immersed when it floats in a glycerol of density 1.3×10³ kg/m³?(density of water=1.0×10³ kg/m³)

Answer 1

To be given in question

In Water float

$l$ =8cm

$\rho_{w}=1.0\times10^3 kg/m^3$

In glycerol float

$\rho_{g}=1.3\times10^3kg /m^3$

To be asked in question

$l'=?$

We know that formula

$[\rho_{w}glA]_{w}=[\rho_{g}gl'A]_{g}$

$\rho_{w}l=\rho_{g}l'$

Put value

$1.00\times10^3\times8=1.3\times10^3\times l'$

$l' =6.15 cm$