Electric Charge...

Two identical tiny metal balls carry charges of $$+3nC$$ and $$-12nC$$. They are $$3cm$$ apart. The balls are now touched together and then separated to $$3cm$$. The force on them is :

A charge of $$1\mu C$$ is divided into two parts such that their charges are in the ratio of $$2 : 3$$. These two charges are kept at a distance 1m apart in vaccum. Then, the electric force between them (in newton) is :

Two charges $$Q_{1}$$ and $$Q_{2}$$ are placed in vacuum at a distance d and the force acting between them is $$5$$ units. If a medium of dielectric constant $$2$$ is introduced around them, the net force now will be :

If the force between two charged objects is to be left unchanged even though the charge on one of the object is halved keeping the other same, the original distance (d) of separation should be changed to :

Two identical metallic spheres A and B carry charges $$+Q$$ and $$-2Q$$ respectively. The force between them is 'F' newton, when they are separated by a distance 'd' in air. The spheres are allowed to touch each other and are moved back to their initial position. The force between them now is:

A particle that carries a charge $$-q$$ is placed at rest in uniform electric field $$10\ N/C$$. It experiences a force and moves in a certain time t, it is observed to acquire a velocity $$10\vec{i}-10\vec{j}$$ m/s. The given electric field intersects a surface of area $$A$$ $$m^{2}$$in the X -Z plane. Electric flux through surface is:

Two point charges $$+4C$$ and $$+6C$$ repel each other with a force F. If a charge $$-5C$$ is given to each of these charges, the force becomes:

Two point charges of $$2C$$ and $$-6C$$ attract each other with a force of $$12N$$. A charge -$$2C$$ is added to $$- 6C$$ charge now, then the force between them is :

A cube is arranged such that its length, breadth, height are along X,Y and Z directions. One of its corners is situated at the origin. Length of each side of the cube is $$25\ cm$$ . The components of electric field are $$E_{x}=400\sqrt{2}\ N/C,\ E_{y}=0$$ and $$E_{Z}=0$$ respectively. The flux coming out of the cube at one end, whose plane is perpendicular to X axis, will be:

Two charged particles having charges $$+25\mu C$$ and $$+50\mu C$$ are separated by a distance of 8 cm. The ratio of forces on them is: