The block in the drawing has dimensions l0×2l0×3l0,where l0 =0.5 m. the block has a thermal conductivity of 200 j/(s·m·c˚). in drawings a, b, and c, heat is conducted through the block in three different directions; in each case the temperature of the warmer surface is 37 ˚c and that of the cooler surface is 7 ˚c determine the heat that flows in 4 s for each case.

Explanation:

Given:

REFER THE ATTACHED IMAGE FOR THE REFERENCE

The rate of heat flow using Fourier's law of conduction is given as:

Now the amount heat flow perpendicular to the pink surface:

Now the amount heat flow perpendicular to the orange surface:

Now the amount heat flow perpendicular to the green surface:

explanation:

could i give you a exaplo that could you?

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.