Why is ultrasound imaging considered safer than X-ray imaging for monitoring the development of a fetus during pregnancy?

Which of the following best describes the physical structure of an electromagnetic wave as it propagates through space?

True or False: On a graph showing frequency ($f$) on the vertical axis and wavelength ($\lambda$) on the horizontal axis for electromagnetic waves in a vacuum, the relationship is represented by a straight line with a positive slope.

Which of the following waves requires a physical medium (such as air or water) to propagate and is classified as a longitudinal wave?

While X-rays are produced by the interaction of fast electrons with a metal target, gamma rays are distinct because they are produced during __________ transitions within an atom.