Question

What can happen to the mass of a body on charging by conduction?
\[{\text{A}}{\text{.}}\] Increase
\[{\text{B}}{\text{.}}\] Decrease
\[{\text{C}}{\text{.}}\] Increase or decrease
\[{\text{D}}{\text{.}}\] None of these

Answer 1

Hint- Here, we will proceed by defining the process of acquiring charge through conduction. Then, we will see what happens with the mass of the body when a either positive or negative charge is acquired.

Complete step-by-step solution -
Charging by conduction requires interaction with a neutral body by a charged object. Suppose a positively charged aluminium plate is connected to a sphere of neutral metal. As a result of touch by the charged aluminium plate the neutral metal sphere is charged. Also, assume that the top plate of a neutral needle electroscope is hit by a negatively charged metal sphere. As a result of touch by the metal sphere, the neutral electroscope is charged.
Each of the examples corresponding to the process of charging by conduction involves contact between the object being charged and the neutral object. Contrary to induction, where the charged object is brought near but never touched to the charged object, conduction charging requires allowing the charged object's physical relation to the neutral object. Since conductive charging requires contact, it is also called charging by contact.
Let us suppose, we have a neutrally charged body. If the body loses electrons (i.e., electrons are removed from the body) it becomes positively charged and if the body gains electrons (i.e., electrons are added to the body) it becomes negatively charged. When a positive charge is acquired by a body, the mass of the body decreases due to the removal of the electron. When a negative charge is acquired by a body, the mass of the body increases due to the addition of the electron.
Therefore, the mass of a body on charging by conduction can increase or decrease according to the sign of the charge acquired by the body.
Hence, option C is correct.

Note- In general, there are two kinds of charges which are positive charges and negative charges. It is important to note that any two like charges (i.e., either both positive charges or both negative charges) repel each other and any two unlike charges (i.e., one positive charge and other negative charge) attract each other.