Unit: Waves
Year: 1993 Question#: 55
Question: The diagram at the right represents the path of periodic waves passing from medium A into medium B. As the waves enter medium B, their speed
(1 ) decreases
(2 ) increases
(3 ) remains the same
What is this question really asking?
Explanation by: Gabrielle
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Answer 1
decreases
INCORRECT
If a wave enters a slower medium its speed decreases and it bends toward the normal. The wave in medium B bends away from the normal. return to top
Answer 2
increases
CORRECT
When a wave enters a faster medium its speed increases and it bends away for the normal. The waves in medium B bend away from the normal so their speed increases. return to top
Answer 3
remains the same
INCORRECT
If a wave enters a different medium it will bend toward or away from the medium, depending on the whether the medium is slower or faster. Because the wave bends away from the medium, we know that there was a change in the wave's speed within the medium. return to top
What's this question really asking?
When a wave bends away from the normal does it enter a fast or a slow medium? return to top
