*Question E0A08:
What does SAR measure?*  

*Correct Answer is  C: The rate at which RF energy is absorbed by the body*  

### AI Response: (may contain errors)  

SAR, or Specific Absorption Rate, measures the rate at which RF (radio frequency) energy is absorbed by the body. 

### Explanation of the Correct Answer:
- **Correct Answer: C: The rate at which RF energy is absorbed by the body**
  - SAR is expressed in watts per kilogram (W/kg) and is used to assess the exposure of the human body to RF energy from devices like cell phones and radios. Regulatory agencies set limits on SAR to ensure safety.

### Explanation of Incorrect Answers:
- **A: Signal attenuation ratio**
  - This term refers to the reduction in signal strength as it travels through a medium, not related to how RF energy is absorbed by the body.

- **B: Signal amplification rating**
  - This would pertain to how much a signal is amplified by a device, which is unrelated to absorption of RF energy by biological tissues.

- **D: The rate of RF energy reflected from stationary terrain**
  - This describes how RF signals behave when they encounter surfaces, not how they are absorbed by the human body.

### Useful Information:
- SAR is important for evaluating the safety of RF exposure, especially in devices that are used close to the body.
- Regulatory limits for SAR are typically set at 1.6 W/kg for localized exposure (like cell phones) in the U.S. 

Understanding SAR is crucial for ensuring that devices comply with safety standards and do not pose health risks to users.