Final answer:
Streams with broad, shallow channels and narrow, deep channels have a higher flow velocity than those with semi-circular channels.
Step-by-step explanation:
The statement is True. Streams with broad, shallow channels and narrow, deep channels have a higher flow velocity compared to those with semi-circular channels.
This is because the flow velocity of a fluid is inversely related to its cross-sectional area. When a fluid flows into a narrower channel, the streamlines become closer together, resulting in a decrease in cross-sectional area. According to the principle of continuity, the flow rate must remain constant, so as the cross-sectional area decreases, the velocity of the fluid increases.
For example, when a river widens, its flow rate decreases and the current slows down, whereas a narrow and deep channel has a higher flow velocity.