What property of an object is related to the average kinetic energy of the particles in that object

Temperature of the object

Explanation:

According to kinetic theorem of gases, the temperature of a gas is a measure of the of the average kinetic energy of the gas particle.

A particle can either exist as solid, liquid or gas.

For solid, the particles are fixed as they rotates and vibrate about a mean position.

The particle of an object is a solid particle.

In accordance to kinetic theorem, the temperature of an object related to the average kinetic energy of the particles in the object.\

Temperature: This can be defined as the degree of hotness or coldness of an object.

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.