Is solar system a natural system or human-made system​

Which lists the pairs of plates in order from least to greatest in terms of the work done to move the electron?

The magnitude of the poynting vector of a planar electromagnetic wave has an average value of 0.939 w/m^2 . the wave is incident upon a rectangular area, 1.5 m by 2.0 m, at right angles. how much total electromagnetic energy falls on the area during 1.0 minute?

Decreased sensitivity to an unchanging stimulus is known as