Electric Charge...

Two charges $$q$$ and $$-q$$ placed at $$(a, 0)$$ and $$(-a, 0)$$ on the x-axis. Another charge $$2q$$ is taken from $$(0,0)$$ to $$(0, a)$$, then the work done to do so 

If an electron is projected in a uniform perpendicular electric field, then its trajectory will be a

A negative charge is placed at the midpoint between two fixed equal positive charges, separated by a distance $$2d$$. If the negative charge is given a small displacement $$x (x << d)$$ perpendicular to the line joining the positive charges, how
the force (F) developed on it will approximately depend on $$x$$ ?

A charged oil drop is suspended in a uniform field of 3 x 10⁴  v/m so that it neither falls nor rises. The charge on the drop will (Take the mass of the charge  = 9.9 x 10^-15 kg  and g = 10 m/s²  )

In Region of Electric field Given by $$\vec{E} = (Ax + B) \hat{i}$$. Where $$A = 20$$ unit and $$B = 10$$ unit. If Electric potential at $$x = 1\,m$$ is $$V_1$$ and at $$x = -5 \,m$$ is $$V_2$$. Then $$V_1 - V_2$$ is equal to

Two positive charges and an negative charge, all of equal magnitude, are set at the corners of an equilateral triangle.
Which diagram best represents the electric field surrounding the charges?

Two masses $$M_1$$ and $$M_2$$ carry positive charges $$Q_1$$ and $$Q_2$$, respectively. They are dropped to the floor in a laboratory setup from the same height where there is a constant electric field vertically upwards $$M_1$$ hits the floor before $$M_2$$. Then :

An electron passes into the space between two parallel plates that are 5.0 cm apart and which
are maintained at electric potentials of +2000V and -500V, respectively. 
What is the electric force on the electron? 

One brass plate is inserted between two charges. The force between two charges will

Three point charges $$4q,Q$$ and $$q$$ are placed in a straight line of length$$L$$  at points $$0,\dfrac{L}{2}$$ and $$L$$ respectively. The net force on charge $$q$$ is zero. The value of $$Q$$ is