Electric Charges and Fields

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 $$R$$)