An insulator (non-conductor) can be charged by
a. conduction (b) induction (c) friction

Options

A. a,c
B. b,c
C. c only
D. b only

Explanation

To determine how an insulator can be charged, let's analyze the three options provided: conduction, induction, and friction.

### Step-by-Step Solution:

1. **Understanding Insulators**:
- An insulator is a material that does not allow the flow of electric charge (electrons). This is the fundamental property of insulators.

2. **Option A: Conduction**:
- Conduction involves the transfer of charge through the movement of electrons. When a charged object comes into contact with a conductor, electrons can flow from one to the other.
- Since insulators do not allow electron flow, they cannot be charged by conduction.
- **Conclusion**: Option A is incorrect.

3. **Option B: Induction**:
- Induction is a process where a charged object can induce a charge in a nearby object without direct contact, often involving grounding.
- In the case of insulators, since they do not allow the movement of electrons, induction cannot occur effectively.
- **Conclusion**: Option B is also incorrect.

4. **Option C: Friction**:
- Charging by friction involves rubbing two different materials together, which can transfer electrons from one material to another.
- For example, when a comb is rubbed through hair, electrons are transferred, resulting in the comb acquiring a negative charge.
- Insulators can be charged through this method because the friction allows for the transfer of charge without the need for electron flow through the material itself.
- **Conclusion**: Option C is correct.

### Final Answer:
The insulator can be charged by **(c) friction**.

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