What is significant about the year 1831?

• A. Michael Faraday discovers electromagnetic induction, laying the foundation for radio wave technology
• B. Hulsmeyer patents the first radar-like device
• C. The ferry Kalakala receives FCC Radar License No.001
• D. Radar is invented by Marconi

Answer: (A)

The key idea here is electromagnetic induction: Faraday showed that a changing magnetic field can induce an electric current. This discovery reveals that electricity and magnetism are intertwined and that changing magnetic environments can generate electrical energy. That link is foundational because it underpins how generators and transformers work, and it points to the possibility that changing electromagnetic fields can carry energy through space—setting up the understanding that leads to radio waves and wireless communication. The other options describe radar-related developments that happened much later, so they don’t align with the year 1831.