One type of medical imaging process is called positron emission tomography. Radioactive material is injected into a patient; during the radioactive decay the material emits a positron, which then interacts with an atomic electron, emitting gamma rays, which are detected by the imager. This gamma ray emission process is called:
A) pair production
B) annihilation
C) absorption
D) alpha decay
E) fission
B) annihilation
You might also like to view...
A loop of gas following the magnetic field lines between sunspots' poles is:
A) a flare. B) a ray. C) a coronal hole. D) a prominence. E) a coronal mass ejection.
An iron core in a transformer
A) guides magnetic field lines. B) shields unwanted external electric or magnetic fields. C) separates the primary and secondary regions. D) reduces energy losses.
What are cosmic rays?
A) another name for gamma rays and X-rays B) fast moving dust particles in the interstellar medium C) subatomic particles that travel close to the speed of light D) lasers used as weapons by extraterrestrials
A bullet is fired through a board, 14.0 cm thick, with its line of motion perpendicular to the face of the board. If it enters with a speed of 450 m/s and emerges with a speed of 220 m/s, what is the bullet's acceleration as it passes through the board?
A. ?500 km/s2 B. ?550 km/s2 C. ?360 km/s2 D. ?520 km/s2 E. ?275 km/s2