Electric Charges and Fields Test - 7

The Charges were named positive and negative by the American scientist Benjamin Franklin.

When the glass rod is rubbed with the wool, both the glass rods acquire the charge of the same polarity while the wool acquire the charge of opposiste polarity from the glass rod.

The like charges are acquired by the glass rod.

As we know that the unlike charges attract each other and like charges repel each other.

When two glass rod are bought together, they repel each other and moves away from each other.

 Initially the charge on the glass rod is neutral.

By the convention,

When the glass rod is rubbed with silk, the charge on the glass rod is positive and the silk is negative.

The property which differentiates the two kinds of charge i.e positive and negative charge is polarity.

The Gold-leaf electroscope is use to detect the charge on the body.

It consists of vertical metal rod housed in a box, with two thin gold leaves attached at the bottom end. The degree of divergence is an indicator of the amount of the charge.

As the body is charged by rubbing it can take two charges positive or negative.

Since initially tie body is neutral.

If the body get positive charge which is due to loss of the electrons inside the body thus the weight of the body decreases as during the process of rubbing it is transferred to another body due to deficiency of electrons in first body the mass of the first body decreases.

If the body receives negative charge this means it has accepted electrons from another body due to which the new electrons accepted by the body will increase the mass the body.

Thus, we can conclude that if a body is charged by rubbing the mass of the body may slightly increase or decrease depending upon the charge on the body.

The law of conservation of mass state that the total electric charge of an isolated system is conserved.

Thus we can conclude universe to be the isolated system which have equal numbers of both the two types of the charges.

From the above statement, we can say that

Total charge in universe, q _universe= (q⁺ +(-q)^-)× e^- = 0 e^-

q⁺ denotes the amount of the positive charge

q^- denotes the amount of the negative charge

e^- is the electronic charge on electron.

Thus, the total charge in the universe is constant