What do herbicides primarily interfere with?

$A$ uniform cube of side $a$ and mass $m$ rests on a rough horizontal table. $A$ horizontal force $F$ is applied normal to one of the faces at a point that is directly above the centre of the face,at a height $\frac{3a}{4}$ above the base. The minimum value of $F$ for which the cube begins to tilt about the edge is (Assume that the cube does not slide):

From a solid sphere of mass $M$ and radius $R$,a cube of maximum possible volume is cut. The moment of inertia of the cube about an axis passing through its centre and perpendicular to one of its faces is

According to Graham's law,the rate of diffusion of $CO$,$O_2$,$N_2$,and $CO_2$ follows the order:

$A$ wire of area of cross-section $10^{-6} \ m^2$ is increased in length by $0.1\%$. The tension produced is $1000 \ N$. The Young's modulus of the wire is:

$A$ plane mirror is placed at the bottom of a tank containing a liquid of refractive index $\mu$. $P$ is a small object at a height $h$ above the mirror. An observer $O$,vertically above $P$ outside the liquid,sees $P$ and its image in the mirror. The apparent distance between these two will be