What will happen when we rub a glass rod with silk cloth?

Options

A. Some of the electrons from the glass rod are transferred to the silk cloth.
B. The glass rod gets positive charge and silk cloth gets negative charge.
C. New charge is created in the process of rubbing.
D. both (a) and (b) are correct.

Explanation

When we rub a glass rod with silk cloth, the following sequence of events occurs:

### Step-by-Step Solution:

1. **Initial State**: Before rubbing, both the glass rod and the silk cloth are electrically neutral. This means that the number of protons (positively charged) equals the number of electrons (negatively charged) in both materials.

2. **Rubbing Process**: When the glass rod is rubbed with the silk cloth, electrons are transferred from the glass rod to the silk cloth. This transfer occurs due to the difference in their affinities for electrons.

3. **Charge Transfer**: Let's assume that during the rubbing process, 5 electrons are transferred from the glass rod to the silk cloth.

4. **Final Charge on Glass Rod**: After losing 5 electrons, the glass rod now has a deficiency of electrons. Since it originally had a neutral charge, losing electrons results in a net positive charge. Therefore, the charge on the glass rod becomes +5e (where e is the elementary charge).

5. **Final Charge on Silk Cloth**: The silk cloth, having gained 5 electrons, now has an excess of electrons. Since it was initially neutral, gaining electrons results in a net negative charge. Thus, the charge on the silk cloth becomes -5e.

6. **Net Charge of the System**: The total charge of the system (glass rod + silk cloth) remains zero. The positive charge on the glass rod (+5e) and the negative charge on the silk cloth (-5e) cancel each other out, resulting in a net charge of zero for the entire system.

7. **Conclusion**: Therefore, when a glass rod is rubbed with silk cloth, electrons are transferred from the glass rod to the silk cloth, resulting in the glass rod acquiring a positive charge and the silk cloth acquiring a negative charge.

### Final Answer:
- **Option 4**: Both A and B are correct: Electrons are transferred, and the glass rod becomes positively charged while the silk cloth becomes negatively charged.