A simplified experiment showing the setup of a pith ball (a circular object) attached by a string to an insulated stand. The researcher tested how far away a charged glass rod can be held while still causing an attraction to the pith ball. Which statements accurately describe this experimental design? Select ALL that apply. A) An appropriate control could be a non-charged glass rod used for comparison. B) The dependent variable is the distance of the glass rod is from the pith ball. C) The independent variable is the distance of the glass rod is from the pith ball. D) The dependent variable is the level of attraction that the pith ball has to the charged rod. E) The independent variable is the level of attraction that the pith ball has to the charged rod.

temp rises, and expansion

the answer for apex is the lowest

the assestment will probley apele with cause and effect

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.