Question

In the diagram below, light from the Sun strikes a beach (Z). The beach sand gains heat then warms the air that is immediately above it (X) and the sand that is immediately below it (Y). The warm air rises and is replaced by cool air (W).


2
Which point indicates convective heat transfer?
A.
Y
B.
W
C.
Z
D.
X

Answer 1

D. X

Explanation: Convection is heat transfer by bulk movement of a fluid (air). The air at X is warmed by the sand and rises, which is convective heat transfer. (Z is radiation from the Sun; Y is conduction into the sand; W is the cool air replacing the rising air.)