physics ncert solutions class 11th

The height 'h' at which the weight of a body will be the same as that at the same depth 'h' from the surface of the earth is (Radius of the earth is R and effect of the rotation of the earth is neglected)

If the potential energy between two molecules in given by U = A/r¹² - B/r? then at equilibrium, separation between molecules, and the potential energy are:

Nitrogen has is at 300° temperature. The temperature (in K) at which the rms speed of a H? molecule would be equal to the rms speed of a nitrogen molecule, is (Molar mass of N? gas 28 g)

A hollow spherical shell at outer radius $\mathrm{R}$ floats just submerged under the water surface. The inner radius of the shell is r. If the specific gravity of the shell material is $\frac{27}{8}$ w.r.t water, the value of r is.

The sum of two forces  $\vec{P}$ and $\vec{Q}$ is $\vec{R}$ such that $\left|\vec{R}\right|=\left|\vec{P}\right|$ . The angle $\theta$ (in degrees) that the resultant of $2\vec{P}$ and $\vec{Q}$ will make with $\vec{Q}$ is,               

The plot that depicts the behavior of the mean free time $\tau$ $$ (time between two successive collisions) for the molecules of an ideal gas, as a function of temperature $\left(T\right)$ $$ , qualitatively, is: (Graphs are schematic and not drawn to scale)

Calculate the value of mean free path (λ) for oxygen molecules at temperature 27° C and pressure 1.01*10⁵ Pa. Assume the molecular diameter 0.3 nm and the gas is ideal. (k = 1.38 x 10⁻²³ JK⁻¹)

The number of molecules in one litre of an ideal gas at 300K and 2 atmospheric pressure with mean kinetic energy 2 * 10? J per molecule is: