$A$ man is sitting in a boat which is floating in a pond. If the man drinks some water from the pond,the level of water in the pond will

$A$ small solid ball is dropped from a height above the free surface of a liquid. It strikes the surface of the liquid at $t = 0$. The density of the material of the ball is $500 \ kg/m^3$ and that of the liquid is $1000 \ kg/m^3$. If the ball comes momentarily to rest at $t = 2 \ s$,then the initial height of the ball from the surface of the liquid was ..... $m$ (neglect viscosity).

Assertion $(A)$: $A$ helium-filled balloon does not rise indefinitely in the air but halts after a certain height.
Reason $(R)$: Viscosity opposes the motion of the balloon. Choose any one of the following four responses:

$A$ sphere of diameter $7 \, cm$ and mass $266.5 \, g$ floats in a bath of a liquid. As the temperature is raised,the sphere just begins to sink at a temperature $35^{\circ} C$. If the density of the liquid at $0^{\circ} C$ is $1.527 \, g/cm^3$,then neglecting the expansion of the sphere,the coefficient of cubical expansion of the liquid is:

The reading of a 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 submerged in water. The specific gravity of the block must be therefore ............

$A$ cube of ice has an iron piece frozen inside it. The cube floats in a beaker filled with water. When the ice melts, the level of water in the beaker: