What principle of light’s behavior can be used to make a far away object appear closer and also make a small object appear larger?

Explanation:

Refraction is the change in the direction of the wave passing from one medium to another.

The change in the direction of the propagation of any wave is due to the different speed at different points.

A far away object appears closer and a small object appears larger.

Take an example. Suppose, an object lies in water.

A far away object appears closer. The angle from which the rays of light reach the observer is larger than the angle that it makes in air.

This makes the angular size larger to the observer's eye which makes the object look larger relative what it looks in air. Similar but vice versa condition occurs in the case when a small object appears larger.

Therefore, refraction can be used to make a far away object appear closer and also make a small object appear larger.

most voltage drop calculators want the distance between the source and destination. then internally, they double it so both the source and return wires are calculated. but you need to know which distance the calculator uses so you're not half of what you should be or double what you should be.

most circuit breakers will not take a #6 directly, so the electrician will have to splice on a smaller pigtail. you also have to upsize the grounding wire when you upsized the ungrounded (hot) wire (see note in 250.122). this will preclude using most cable assemblies, as a cable with #6 copper will most likely only have a #10 grounding conductor. you need a #6 grounding conductor if the circuit is 20a. a #8 cable is no better, as it will have a #10 grounding conductor too. but most 20a breakers will take a #8 directly.

in your related post, you didn't say what type of load this is. if it is a light or heater, voltage drop won't be a big issue. if this is a motor, the current needs are huge at startup and the voltage drop can pose a problem. if this is a motor, knowing if the motor is under much load during startup will answer the voltage drop effect (a saw is easier to start than a compressor).