Question

Allen made a diagram to compare radiation and conduction.

A Venn diagram shows 2 intersecting circles, with the left circle labeled radiation and the right circle labeled conduction. There is an Y in the overlapping section.
Which label belongs in the area marked Y?

Must involve temperature differences between substances or objects
Occurs when molecules are in direct contact
Involves the movement of fluids based on density differences
Can occur where there is little or no matter

Answer 1

"Must involve temperature differences between substances or objects."

Reason: Both conduction and radiation transfer thermal energy because of temperature differences. The other statements describe conduction only (direct molecular contact), convection (fluid movement/density differences), or radiation only (can occur with little or no matter).