*Question T6A11:
Which of the following battery chemistries is not rechargeable?*  

*Correct Answer is  B: Carbon-zinc*  

### AI Response: (may contain errors)  

The correct answer to the question is **B: Carbon-zinc**. Here's the explanation:

1. **Why the correct answer is correct:**
   - Carbon-zinc batteries are primary batteries, meaning they are designed for single-use and cannot be recharged. Once the chemical reactions that produce electricity are exhausted, the battery must be disposed of and replaced.

2. **Why the other choices are incorrect:**
   - **A: Nickel-cadmium (NiCd)**: This is a rechargeable battery chemistry. It can be recharged multiple times, making it suitable for applications where frequent battery replacement would be impractical.
   - **C: Lead-acid**: This is also a rechargeable battery type. Commonly used in automotive applications, lead-acid batteries can be recharged many times, which is essential for their use in vehicles.
   - **D: Lithium-ion**: This is a widely used rechargeable battery chemistry, known for its high energy density and efficiency. It is commonly found in portable electronics and electric vehicles.

3. **Useful rules of thumb:**
   - **Primary vs. Secondary Batteries**: 
     - Primary batteries (like carbon-zinc) are not rechargeable.
     - Secondary batteries (like NiCd, lead-acid, and lithium-ion) are designed to be recharged.
   - **Applications**: 
     - Use primary batteries for devices with low power consumption and infrequent use.
     - Use rechargeable batteries for high-drain devices or those that are used frequently.

Understanding these distinctions will help you identify battery types and their applications effectively for the exam.