Answer: Option B
:
B
Given,
Length of each side of the cube, $l=10cm=0.1m$
Density of water, $\rho =1000kg{m}^{-3}$
Acceleration due to gravity, $g=10m{s}^{-2}$
Volume of the cube, $V=l^3=(0.1{)}^3=0.001m^3$
Archimedes' principle states that the buoyant force acting on an object is equal to the weight of the fluid displaced by it.
In the given case, volume of cube is equal to the volume of water displaced.
Mass of waterdisplaced (m) = Density of water $\times$ Volume of water displaced
$\Rightarrow m=1000kg{m}^{-3}\times 0.001m^3$
$=1kg$
Weight of water displaced, W =mg
$\Rightarrow W=1\times 10$ =$10N$
Hence, the buoyant force is $10N$.