When a plastic pen is rubbed in dry hair, it attracts tiny pieces of paper. Which force is involved in this process ?

Options

A. Electrostatic force
B. Muscular force
C. Gravitational force
D. Frictional force

Answer

**Step-by-Step Solution:**

1. **Understanding the Initial Condition:**
- When a plastic pen is rubbed against dry hair, both objects become charged. This happens due to the transfer of electrons from one material to another.

**Hint:** Think about what happens when two different materials are rubbed together.

2. **Charge Generation:**
- The plastic pen gains a charge (let's say positive), while the dry hair acquires an equal amount of negative charge. This is due to the principle of conservation of charge, where the total charge remains constant.

**Hint:** Remember that charges come in pairs: positive and negative.

3. **Induction of Charge in Paper:**
- When the charged pen is brought near tiny pieces of paper, it induces a charge in the paper. If the pen is positively charged, it will attract electrons from the paper, creating a negative charge on the side of the paper closest to the pen.

**Hint:** Consider how charges interact when they are close to each other.

4. **Attraction of Opposite Charges:**
- The negatively charged side of the paper is attracted to the positively charged pen. This attraction occurs because opposite charges attract each other.

**Hint:** Recall the basic rule of electrostatics: like charges repel, and opposite charges attract.

5. **Identifying the Force:**
- The force that causes the attraction between the charged pen and the pieces of paper is known as the electrostatic force.

**Hint:** Think about the types of forces that arise from charged objects.

**Final Answer:**
The force involved in this process is the **electrostatic force**.

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