Question

In: Physics

A glass marble is rubbed against a piece of silk. As a result the piece of fabric acquires extra electrons

A glass marble is rubbed against a piece of silk. As a result the piece of fabric acquires extra electrons. What happens to the glass marble? (Select all that apply)
The marble has lost the same number of electrons acquired by the piece of silk.
The marble acquires a positive charge and repels the piece of silk.
The marble acquires a negative charge and attracts the piece of silk.
The marble has acquired the same number of electrons acquired by the piece of silk.
The marble acquires a positive charge and attracts the piece of silk.
The marble acquires a negative charge and repels the piece of silk.

 

Solutions

Expert Solution

Concepts and reason

The concepts required to solve the given question is electrostatic force. Initially, for the number of electrons by the piece of silk, apply the law of conservation of charge and for the nature of force between the marble and silk, use the concept of Coulomb's force.

Fundamentals

In an isolated system, the total charge remains conserved; that is, when a glass rod is rubbed against a piece of silk, the marble loose electrons and then becomes more electron-deficient, which leads to acquiring of the positive charges on the glass marble and the piece of silk acquires extra electrons and becomes negatively charged. According to Coulomb's law, the charges having the same sign repel each other, and the charges having different signs always attract each other.

When the glass marble is rubbed with a piece of silk, some electrons from the marble get transferred to the piece of silk, and hence, the marble acquires a positive charge, and the silk acquires a negative charge.

Thus, the marble does not acquire a positive charge and does not repel the piece of silk; the marble doesn’t acquire a negative charge. It does not attract the piece of silk, the marble doesn’t acquire a negative charge and doesn’t repel the piece of silk, and the marble has acquired the same number of electrons acquired by the piece of silk.

The length of the long wire is equal to 10 cm. It is to be converted into m to find the value of the magnetic field in Tesla.

It is given that the piece of silk fabric acquires extra electrons when a glass marble is rubbed against it. Due to the marble's rubbing action on the silk piece, the marble loses few electrons acquired by silk fabric pieces.

The number of electrons lost by the marble must be the same as that of the number of electrons gained by the silk piece.

This is by the law of conservation of charges. Thus, the marble has lost the same number of electrons acquired by the piece of silk.

The marble has lost the same number of electrons acquired by the piece of silk.

According to the law of conservation of charges, the charge must remain conserved in an isolated system; that is, the charge lost must be equal to the charge gained.

Since marble has lost electrons, it gains the positive charge, and the silk piece gains equal and opposite negative charge due to the addition of electrons. The positive and negative charge exerts an attractive force on each other.

This is by Coulomb’s law. Thus the marble acquires a positive charge and attracts the piece of silk.

The marble acquires a positive charge and attracts the piece of silk.

According to Coulomb’s law, the same sign charges repel each other, and the different sign charges attract each other.


The marble has lost the same number of electrons acquired by the piece of silk.

The marble acquires a positive charge and attracts the piece of silk.

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