How do I find the amplitude of the combined signal?

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Homework Help Overview

The discussion revolves around finding the amplitude of a combined signal, specifically in the context of wave interference and electric field strength. Participants explore the relationship between phase difference and amplitude, as well as the appropriate units for measuring amplitude in this scenario.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the necessity of memorizing specific equations related to combined waves and question the placement of the sine term in the equation. There is also inquiry into the meaning of amplitude units, particularly "μV/m," and how they relate to electric field strength.

Discussion Status

The conversation is ongoing, with participants seeking clarification on the relationship between amplitude and electric field strength. Some guidance has been provided regarding the interpretation of units and the significance of the sine function in determining amplitude, but no consensus has been reached on memorization versus understanding of the underlying concepts.

Contextual Notes

Participants are navigating the implications of units in the context of their coursework, particularly how amplitude is defined in relation to electric fields rather than physical distance. There is an underlying assumption that understanding these concepts is crucial for their homework tasks.

alexdr5398
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Homework Statement


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Homework Equations


Δφ = 2π (Δr/λ)

The Attempt at a Solution


I understand how to get the phase difference, but is the equation for the combined wave (second last line) just something I should memorize?

Also, where does the sin term go in the last line? And why are the units for amplitude "μV/m"? Aren't V/m the units for electric field?
 
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alexdr5398 said:
I understand how to get the phase difference, but is the equation for the combined wave (second last line) just something I should memorize?
Probably. It's that or memorize the trig identity for sin(A) + sin(B) which is used to derive it. While the latter is more useful in general, the former is more likely to be expedient in the context of your current coursework.

alexdr5398 said:
Also, where does the sin term go in the last line? And why are the units for amplitude "μV/m"? Aren't V/m the units for electric field?
The sin function varies between + and - 1 as t varies, so what's its magnitude?. The rest are constant terms.

The "μ" in μV stands for "micro". Thus the signal strength is being given in microvolts per meter.
 
gneill said:
The sin function varies between + and - 1 as t varies, so what's its magnitude?. The rest are constant terms.

Oh I see. So the maximum y value is the amplitude, and that occurs then the sin term is 1.

gneill said:
The "μ" in μV stands for "micro". Thus the signal strength is being given in microvolts per meter.

I know what "μ" is, but isn't the amplitude usually measured in metres? Why is the unit "μV/m" in this case?
 
alexdr5398 said:
I know what "μ" is, but isn't the amplitude usually measured in metres? Why is the unit "μV/m" in this case?
It's the amplitude of the electric field strength that is being measured. That's the change in electric potential with distance, hence volts per meter as the basic unit. The amplitude here is not a physical distance, but a field strength.
 
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gneill said:
It's the amplitude of the electric field strength that is being measured. That's the change in electric potential with distance, hence volts per meter as the basic unit. The amplitude here is not a physical distance, but a field strength.

Oh, alright. thank you.
 

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