Which best describes what happens when light traveling through air enters water at an angle?

a. it moves along straight lines in air and changes direction when it enters water.

b. it moves in a curve in air and moves in straight lines when it enters water.

c. it moves along straight lines in air and continues along the same lines when it enters water.

d. it moves in a curve in air and continues moving in the same curve when it enters water.

The correct choice is

A. It moves along straight lines in air and changes direction when it enters water.

This is because of phenomenon of refraction which  a ray of light experience when it moves from one medium to another medium. The light ray bends away  from the normal to the surface if it travels from denser to rarer medium. The light ray bends towards from the normal to the surface if it travels from rarer to denser medium.

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).

a straight line sloped