1. Radiation is defined as: a. A form of energy carried by waves or streams of particles b. A beam of energy that has the power to penetrate substances and record image shadows on photographic film c. A high-energy radiation produced by the collision of a beam of electrons with là metal target in an x-ray tube d. A branch of medicine that deals with the use of x-rays A B C D 2. The x-ray was discovered by: a. Heinrich Geissler b. Wilhelm Roentgen c. Johann Hittorf d. William Crookes A B c D

1. **A** - Radiation is a broad term encompassing energy transfer by waves or particles. While options B and C describe specific types of radiation (X-rays), they don't define the general term. Option D describes a field of medicine utilizing radiation, not radiation itself.<br /><br />2. **B** - Wilhelm Conrad Roentgen discovered X-rays in 1895. The other individuals listed made contributions to the scientific fields that eventually led to the discovery of X-rays, but they did not discover X-rays themselves.<br />