Wave Question

[ahs4n]

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For a given laser-cavity mode, the standing-wave pattern within a laser cavity can be viewed as a superposition of two traveling waves. Their amplitudes and directions are described by which of the following?

The answer states that its the first answer choice with equal amplitudes and opposite directions. Can someone help me with the wording. I thought a superposition would be constructive interference. Is it destructive interference?

Equal amplitudes; opposite directions
Equal amplitudes; same direction
Different amplitudes; same direction
Different amplitudes; opposite directions

 

[FIREitUP]

For a given laser-cavity mode, the standing-wave pattern within a laser cavity can be viewed as a superposition of two traveling waves. Their amplitudes and directions are described by which of the following?

The answer states that its the first answer choice with equal amplitudes and opposite directions. Can someone help me with the wording. I thought a superposition would be constructive interference. Is it destructive interference?

Equal amplitudes; opposite directions
Equal amplitudes; same direction
Different amplitudes; same direction
Different amplitudes; opposite directions

superposition is just two waves that are "added" together. the interference can be either constructive or destructive (or both if not completely in phase). in the case of that problem, it was destructive with equal amplitudes, i.e. equal amplitudes; opposite directions.

 

[ahs4n]

what gives it away that its destructive interfence though?

 

[fewcherpeedsdoc]

im skeptical of that guys answer...

 

[TraderDoc]

Superposition simply means two waves traveling traveling through the same time in the same medium and interacting with each other.
180 degrees out of phase = destructive interference
Just know that waves rarely completely interact destructively or constructively for the MCAT.

- For your question. The first answer choice is correct because depending on how much in phase or out of phase the two waves are in. The fact that they are traveling in opposite directions means they will interact. Superposition principle states that they will be interact destructively or constructively depending on how much in or out phase (180 degrees, 0 degrees) the waves are.

 

[glia25]

another thing to consider: standing waves that have equal amplitudes at their antinodes must have been formed by 2 waves with the same amplitudes and, as said above they must be traveling in opposite directions in order to interact.

 

[Vihsadas]

Guys, please remember to post your topic specific, study questions in the "Study Q&A Forum", to reduce the overall clutter and improve the readability of the forum main page. I've moved this post there for you. Thanks! 🙂