The fraction of a floating object of volume ${V_0}$ and density ${d_0}$ above the surface of a liquid of density $d$  will be

An ornament weighs $10\, g$ in air and $6\, g$ in water. Density of material of ornament is $20\,\frac{g}{{cc}}$. The  volume of cavity in ornament is ........ $cc$

A hollow sphere has inner volume half the outer volume. Its $4/5\,th$ part is submerged when placed in water. The density of material is

A boat having a length of $3\,metre$ and breadth $2\,metre$ is floating on a lake. The boat sinks by one cm when a man gets on it. Mass of the man is ....... $kg$

A dumbbell is placed in water of density $\rho$ . It is observed that by attaching a mass $m$ to the rod, the dumbbell floats with the rod horizontal on the surface of water and each sphere exactly half submerged as shown in the figure. The volume of the mass $m$ is negligible. The value of length $l$ is

The reading of spring balance when a block is suspended from it in air, is $60\,N$. This reading is changed to $40\, N$ when the block is immersed in water. The specific density of the block is