Two particles with charges q1 and q2 are kept at a certain distance to exert force F on each other. If the distance is reduced to one-fifth, then the force between them is
The sum of the lengths of the edges of a cube is equal to half the perimeter of a square. If the numerical value of the volume pf the cube is equal to one-sixth of the numerical value of the area of the square, then the length of one side of the square is