$A$ cork of density $0.5 \, g/cm^3$ floats on a calm swimming pool. The fraction of the cork's volume which is under water is ........ $\%$

Two pieces of metal when immersed in a liquid have equal upthrust on them; then

$A$ glass flask weighing $390 \ g$,having an internal volume of $500 \ cm^3$,just floats when half of it is filled with water. The specific gravity of the glass is:

Two cylinders of same cross-section and length $L$ but made of two materials of densities $d_1$ and $d_2$ are cemented together to form a cylinder of length $2L$. The combination floats in a liquid of density $d$ with a length $L/2$ above the surface of the liquid. If $d_1 > d_2$,then:

$A$ pendulum has a time period $T$ in air. When it is made to oscillate in water,it acquires a time period $T' = \sqrt{2} T$. The density of the pendulum bob is (density of water $= 1$)

$A$ uniform solid cylinder of density $0.8 \ g/cm^3$ floats in equilibrium in a combination of two non-mixing liquids $A$ and $B$ with its axis vertical. The densities of liquids $A$ and $B$ are $0.7 \ g/cm^3$ and $1.2 \ g/cm^3$,respectively. The height of liquid $A$ is $h_A = 1.2 \ cm$ and the length of the part of the cylinder immersed in liquid $B$ is $h_B = 0.8 \ cm$. Then the length of the part of the cylinder in air is ....... $cm$.