Electric Charges and Fields

goals
Two point charges Q$_a$ and Q$_b$ are positioned at points $A$ and $B$. The field strength to the right of charge $Q_b$ on the line that passes through the two charges varies according to a law represented schematically in figure. (without employing a definite scale) The field strength is assumed to be positive if its direction coincides with the positive direction of the $x$-axis. The distance between the charges is $l = 2l$ cm.
A solid insulating sphere of radius a carries a net positive charge $3 Q$, uniformly distributed throughout its volume. Concentric with this sphere is a conducting spherical shell with inner radius $b$ and outer radius $c$ and having a net charge $-Q$, as shown in figure.
An electric dipole is kept in a uniform electric field, it experiences
Electric current can flow through

Flux passing through the shaded surface of a sphere when a point charge $q$ is placed at the center is (radius of the sphere is $R$)