Unit: Waves
Year: 1997 Question#: 48
Question: Which diagram best represents light emitted from a coherent light source?
(1 )
(2
) 
(3 )
(4
) 
What is this question really asking?
Explanation by: Kristina A
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Answer 1
(1 )
INCORRECT
These are not in phase nor do they have the same frequency. Make sure you know what coherent means. return to top
Answer 2
(2 )
INCORRECT
These waves are NOT in phase nor are their frequency the same. Both factors have to be true for the waves to be coherent. return to top
Answer 3
(3 )
INCORRECT
This is probably the most incorrect because the waves don't even look slightly similar. They don't have the same wavelength or phase. return to top
Answer 4
(4 )
CORRECT
Coherent light means the waves have the same wave length and phase (the peaks and the troughs line up). But you probably knew this since you got the question right. return to top
What's this question really asking?
The question tests your knowledge and understanding of coherent waves. To understand what coherent waves are you have to know what the terms wavelength and frequency and phase are and how they apply to this problem. return to top
