Wave fundamentals in remote sensing/physics: choose the correct statements about wavelength (λ) and amplitude for a travelling wave.
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AThe distance between two successive crests or two successive troughs is called the wavelength.
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BWavelength is measured in metres or fractions of a metre.
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CWavelength is generally denoted by the symbol λ.
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DThe maximum displacement from the midline to the crest is called the amplitude.
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EAll of these
Answer
Correct Answer: All of these
Explanation
Introduction / Context:Many remote sensing concepts—from electromagnetic radiation to acoustic and radar signals—rely on basic wave terminology. A clear understanding of the definitions of wavelength and amplitude is essential for interpreting sensor specifications and spectral responses.
Given Data / Assumptions:
- A sinusoidal travelling wave is assumed for clarity.
- Standard physics notation is used: λ for wavelength.
- Amplitude refers to the peak displacement relative to the mean position.
Concept / Approach:Wavelength is the spatial period of a wave, the distance over which the wave's shape repeats (crest-to-crest or trough-to-trough). Amplitude is the maximum magnitude of displacement from the equilibrium (midline) to the crest (or trough). These definitions underpin spectral resolution (related to λ) and signal strength considerations in sensors.
Step-by-Step Solution:Match definition: consecutive crests/troughs → wavelength.Units: metres and submultiples are standard for spatial distance.Symbol: λ is the universally accepted notation for wavelength.Amplitude: distance from midline to crest (or trough) is the correct definition.Hence, all listed statements are correct.
Verification / Alternative check:Reference wave equations confirm that period in space equals wavelength; amplitude appears as the coefficient controlling peak displacement.
Why Other Options Are Wrong:
- The alternatives are components of the full definition; rejecting any one would be incomplete.
Common Pitfalls:Confusing amplitude with total wave height (crest-to-trough is 2 * amplitude); mixing time period with wavelength.
Final Answer:All of these