Step 1: Understanding the Concept:
The electromagnetic spectrum is classified into various regions based on wavelength and frequency.
Each region interacts with matter in unique ways, making them suitable for specific technological tasks.
The question asks about two specific applications: radar navigation and microwave ovens.
Step 2: Detailed Explanation:
1. Radar Systems: Microwaves have wavelengths in the range of millimeters to centimeters. Because their wavelengths are short, they travel in straight lines and do not experience significant diffraction around everyday obstacles. This allows radar systems to send narrow, precise beams that reflect off objects like aircraft to determine their exact distance and speed.
2. Heating/Cooking: The specific frequency used in kitchen appliances (\(2.45\text{GHz}\)) matches the resonant frequency of water molecules. When these waves pass through food, the alternating electric field causes water molecules to oscillate and flip back and forth billions of times per second. This intense molecular friction generates heat, which transfers energy directly throughout the food.
3. Eliminating other options:
- Radio waves have wavelengths that are too long for high-precision radar.
- Infrared is mostly used for short-range remote controls and thermal imaging.
- Ultraviolet is used for sterilization and has too much energy for safe domestic cooking.
Step 3: Final Answer:
The correct segment of the EM spectrum used for both radar and cooking is Microwaves.