The cells that can be recharged on being drained completely and so they can be reused are know as

Options

A. secondary cells
B. storage cells
C. primary cells
D. both (a) and (b )

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about cells that can be recharged after being completely drained and reused.

2. **Identifying Types of Cells**: There are two main types of cells: primary cells and secondary cells. Primary cells are designed for one-time use, while secondary cells can be recharged.

3. **Defining Secondary Cells**: Secondary cells, also known as rechargeable batteries, are the type of cells that can be recharged after being drained. They undergo reversible chemical reactions, allowing them to regain their charge.

4. **Examples of Secondary Cells**: Common examples of secondary cells include lead-acid batteries (used in cars), nickel-cadmium batteries, and lithium-ion batteries (used in smartphones and laptops).

5. **Conclusion**: Therefore, the cells that can be recharged after being drained completely are known as **secondary cells** or **storage cells**.

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