Tag: charging and discharging

Moving charges constitute electric current.

When rubbed by wool, glass becomes positive and rubber becomes negative. Opposite charges attract. So, the balloon and the glass tumbler will attract each other.

There are 2 types of electrical charges - positive and negative - are said to be opposite types of charge. Consistent with our fundamental principle of charge interaction, a positively charged object will attract a negatively charged object. Oppositely charged objects will exert an attractive influence upon each other. In contrast to the attractive force between two objects with opposite chargess, two objects that are of like charge will repel each other. That is, a positively charged object will exert a repulsive force upon a second positively charged object. This repulsive force will push the two objects apart. Similarly, a negatively charged object will exert a repulsive force upon a second negatively charged object. Objects with like charge repel each other.
Therefore, Like charges repel, while unlike charges attract each other.

Answer is A.

Static electricity is created when two objects are rubbed together, causing an object to give up or gain electrons. The electric charges that are created do not depend on the size of the objects. Therefore, when two bodies are rubbed together, both the bodies transfer electrons to and fro between the bodies and they obtain equal and opposite charges. The body that gives away electrons, gains positive charge and the body that obtains electrons gains negative charge.

Answer is B.

When two bodies are rubbed together, there is transfer of electrons because of friction.
Hence, two uncharged bodies on rubbing, gets equal and opposite charges.

Since the rod which was brought closer was negatively charged the induced charge acquired by the spheres will be positive. 

Electrostatic force is the phenomenon that results from slow-moving or stationary electrical charges. Specifically, electrostatic force is the physical reaction that holds together the electromagnetic field created by subatomic particles, such as electrons and protons. In order for electrostatic forces to remain cohesive, these particles need to independently maintain both positive and negative charges and react to each other accordingly. 
When a balloon is rubbed with a cloth, the electrons from the atoms of the cloth enter the atoms of the balloon and the number of electrons in the atoms of balloon becomes more than the number of protons. Because of that, there is a negative charge in the balloon, and in the cloth the number of electrons in its atoms become less than the number of protons, so it's positively charged.
Therefore, due to this electrostatic force, the balloon sticks to the wall.

Answer is B.

The statement is false because only unlike poles attract each other. Like poles repel each other.

Answer is B.

By symmetry, the charge will distribute evenly over the surface of the bubble. Because like charges repel, they want to move even further apart, the only which way is outward, taking the soap surface with them. Of course, the increase in restoring force of the soap film (surface tension) will at some point be equal and opposite to the electrostatic force, resulting in a new (larger) equilibrium radius.
This will happen to both positive and negatively charged bubbles because of the ionic similarity.
Hence, when the soap bubble is given a negative charge, then its radius will increase.