The discoverer of x-rays was(blank) the discoverer of radioactivity was (blank)

The discoverer of X-rays was Wilhelm Conrad Roentgen.

The discoverer of radioactivity was Henri Bacquerel.

Explanation:

Wilhelm Conrad Roentgen discovered X-rays in early 1895. Roentgen observed a fluorescent glow of crystals on a table near his tube when he was working with a cathode-ray tube in his laboratory, The Cathode ray tube consisted of a glass envelope with positive and negative electrodes encapsulated in it. When a high voltage was applied the air in the tube was evacuated and hence the tube produced a fluorescent glow.

Becquerel had discovered radioactivity in 1896. To study the properties of x-rays he was using naturally fluorescent minerals. He exposed potassium uranyl sulfate to sunlight and then on photographic plates wrapped in black paper, he placed this. He believed that suns's energy would be absorbed by uranium which would then produce X rays. Without any Solar energy  uranium emitted radiation because the images produce in this experiment were strong and clear.