$F_g$ and $F_e$ represent the gravitational and electrostatic forces,respectively,between two electrons situated at a distance of $10 \ cm$. The ratio of $F_g/F_e$ is of the order of:

Four charges $2C, -3C, -4C$ and $5C$ respectively are placed at the corners of a square of side length $L$. Which of the following statements is true for the point of intersection of the diagonals?

What is the angle between the strings and the tension in the strings when two spheres are suspended in a satellite as shown in the figure?

The adjacent diagram shows a charge $+Q$ held on an insulating support $S$ and enclosed by a hollow spherical conductor. $O$ represents the centre of the spherical conductor,and $P$ is a point such that $OP = x$ and $SP = r$. The electric field at point $P$ will be

Two identical point charges are placed at a separation of $l$. $P$ is a point on the line joining the charges,at a distance $x$ from any one charge. The field at $P$ is $E$. $E$ is plotted against $x$ for values of $x$ from close to zero to slightly less than $l$. Which of the following best represents the resulting curve?

Two identical small spheres carry charges of $Q_1$ and $Q_2$ with $Q_1 >> Q_2$. The charges are $d$ distance apart. The force they exert on one another is $F_1$. The spheres are made to touch one another and then separated to distance $d$ apart. The force they exert on one another now is $F_2$. Then $F_1/F_2$ is