$A$ wooden block floats in a liquid with $40\%$ of its volume inside the liquid. When the vessel containing the liquid starts rising upwards with an acceleration $a = g/2$, the percentage of volume inside the liquid is ......... $\%$

$A$ metallic block of density $5 \, g \, cm^{-3}$ and having dimensions $5 \, cm \times 5 \, cm \times 5 \, cm$ is weighed in water. Its apparent weight will be

Four identical beakers contain the same amount of water as shown below. Beaker $A$ contains only water. $A$ lead ball is held submerged in beaker $B$ by a string from above. $A$ same-sized plastic ball,say a table tennis $(TT)$ ball,is held submerged in beaker $C$ by a string attached to a stand from outside. Beaker $D$ contains a same-sized $TT$ ball which is held submerged by a string attached to the bottom of the beaker. These beakers (without the stand) are placed on weighing pans and register readings $w_{A}, w_{B}, w_{C}$,and $w_{D}$ for $A, B, C$,and $D$,respectively. Effects of the mass and volume of the stand and string are to be neglected.

$A$ cubical block of wood of edge $10$ $cm$ and mass $0.92$ $kg$ floats in a tank of water with a layer of oil of relative density $0.6$ to a depth of $4$ $cm$ above the water. When the block attains equilibrium with four of its side edges vertical,which of the following is true?

$A$ small wooden ball of density $\rho$ is immersed in water of density $\sigma$ to a depth $h$ and then released. The height $H$ above the surface of water up to which the ball will jump out of water is

$A$ soft plastic bottle,filled with water of density $1 \text{ g/cc}$,contains an inverted glass test-tube with some air (ideal gas) trapped inside,as shown in the figure. The test-tube has a mass of $5 \text{ g}$,and it is made of thick glass with a density of $2.5 \text{ g/cc}$. Initially,the bottle is sealed at atmospheric pressure $P_0 = 10^5 \text{ Pa}$,such that the volume of the trapped air is $V_0 = 3.3 \text{ cc}$. When the bottle is squeezed from the outside at a constant temperature,the pressure inside increases and the volume of the trapped air decreases. It is observed that the test-tube begins to sink at a pressure $P_0 + \Delta P$ without changing its orientation. At this pressure,the volume of the trapped air is $V_0 - \Delta V$.
Let $\Delta V = X \text{ cc}$ and $\Delta P = Y \times 10^3 \text{ Pa}$.
$(1)$ The value of $X$ is
$(2)$ The value of $Y$ is