The relationship between physical and perceptual quantities

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nao113
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Homework Statement
Imagine and draw a figure to show the relationship between physical and perceptual quantities below as shown in fig.1 with some explanations.
a) Physical and perceptual size of an object
b) Physical and perceptual distance to an object
c) Wavelength of light and color perception (What kind of perceptual quality should be the vertical axis?)
Relevant Equations
In the pictures below
Two-panel figure: left, a Fig.1 graph of sensation intensity (S) against physical stimulus intensity (R), a concave curve with dashed red arrows; right, Fig.2 a visible spectrum bar labelled Wavelength (nm) from 400 to 700 with colours from violet to red.

Worksheet with three empty blank graph grids labelled a) physical and perceptual size, b) physical and perceptual distance, and c) wavelength of light and colour perception, under the instruction to draw relationship figures.


Answer:
Handwritten sketch of two graphs of perceptual quantity against physical quantity: the top, labelled size of an object, rises linearly then has a dashed plateau with arrows labelled 1 and 2; the bottom, labelled distance of an object, is a straight line rising from a point on the horizontal axis.

Did I draw them right?
 
You are asked to provide explanations. Where are they? Specifically, what do the two dashed lines represent in the "Size of an object" figure? You also have to explain the other general features such as why the perceived size or distance do not change as the physical size or distance increase and then all of a sudden there is a linear increase to both of them.
 
There are a couple of difficulties wrt estimating the distance to and size of an object.
1. The two are related; the further away you think it is the larger it will appear to be.
2. for size, are we talking linear dimension, area or volume?

wrt your attempt, consider some extreme examples. How large and far away does the moon look?