5. which of these waves do not require a medium? sound, ocean, radio, or seismic

Your answer is radio waves.

Explanation:

There are two types of waves: Mechanical waves and Electromagnetic waves. Sound, ocean, and seismic waves are mechanical waves, because they require a medium to travel. Radio waves, however, are a form of electromagnetic waves, and therefore do not need a medium to travel. Hope this was helpful! :)

explanation:

v=uf/(u-f)

= 5.-10/(5+10) convex lens has negative focal length