If two solutions have the same osmolarity,they are said to be

Energy of an electron in the ground state of the hydrogen atom is $-2.18 \times 10^{-18} \, J$. Calculate the ionization enthalpy of atomic hydrogen in terms of $J \, mol^{-1}$.

Which of the following is a characteristic of $Pteridophytes$?

Four thin rods of same mass $M$ and same length $l$ form a square as shown in the figure. The moment of inertia of this system about an axis passing through the centre $O$ and perpendicular to its plane is

There is a small hole in a hollow sphere. Water enters it when it is taken to a depth of $40 \,cm$ under water. The surface tension of water is $0.07 \,N/m$. The diameter of the hole is .......... $mm$.

Two spherical soap bubbles of radii $r_1$ and $r_2$ in vacuum combine under isothermal conditions. The resulting bubble has a radius equal to: