Plate tectonics: the earth’s crust is broken up into a series of more-or-less rigid plates that slide around due to motion of material in the mantle below. although the speeds of these plates vary somewhat, they are typically about 5 cm/y (centimeter per year). assume that this rate remains constant over time.1
a. if you and your neighbor live on opposite sides of a plate boundary at which one plate is moving northward at 5 cm/y with respect to the other plate, how far apart do your houses move in a century?
b. los angeles is presently 550 km south of san francisco but is on a plate moving northward relative to san francisco. if the 5.0 cm/y velocity continues, how many years will it take before los angeles has moved up to san francisco?

the minimum amperage that the current in this wire would have to have so that its weight is completely supported by the magnetic force due to earth's field, assuming that no other forces except gravity act on it

where’s the list ? the question is incomplete

scattering of light by tiny particles in air to produce the colors we see on sky, is dependent on the following factors:

(i) wavelength of light

(ii) size of the scattering particle  

(iii) distance traveled by light through the atmosphere.

according to rayleigh's law of scattering, the amount of scattering is inversely proportional to the fourth power of its wavelength. shorter the wavelength, greater is its scattering. hence violet/blue light is scattered more than red.

sun's light is a composite light ( visible light) with wavelengths in the range 400 nm (violet) to 700 nm (red). as sunlight passes through our atmosphere, the molecules of air scatter light according to their wavelengths. during sunrise and sunset, the sun's position is below the horizon. hence light from the sun travels a greater distance in the atmosphere when compared to its position a noon.

as sunlight enters the earth's atmosphere, blue light is scattered away and at the end of its journey in the sky, only red and orange wavelengths remain in the beam.

hence at sunrise and sunset, the sky appears reddish orange.