## **Core Concept**
The concept of radioactivity was first discovered by Henri Becquerel, a French physicist. Radioactivity refers to the process by which unstable atomic nuclei lose energy through radiation. This fundamental concept in nuclear physics has led to significant advancements in medicine, energy, and scientific research.

## **Why the Correct Answer is Right**
Henri Becquerel is considered the "Father of Radioactivity" because he was the first person to discover radioactivity. In 1896, Becquerel observed that uranium salts emitted a form of radiation that could penetrate solid objects and cause photographic plates to become exposed, even in the absence of light. This groundbreaking discovery marked the beginning of radioactivity research.

## **Why Each Wrong Option is Incorrect**
* **Option A:** Ernest Rutherford is known for his pioneering work on the nucleus and radioactivity, but he is not considered the "Father of Radioactivity." He made significant contributions to the understanding of radioactivity, including the discovery of alpha, beta, and gamma radiation.
* **Option B:** Marie Curie is famous for her work on radioactivity and the discovery of elements polonium and radium. While she made crucial contributions to the field, she built upon Becquerel's initial discovery.
* **Option D:** Wilhelm Conrad Röntgen is known for discovering X-rays, a form of electromagnetic radiation. Although his work is related to radiation, it is distinct from radioactivity.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that Henri Becquerel's discovery of radioactivity was a serendipitous finding. He initially aimed to study the properties of uranium salts under different lighting conditions but ended up discovering radioactivity when he left an unexposed photographic plate near a sample of uranium salt.

## **Correct Answer:** C. Henri Becquerel