Just about everyone at one time or another has been burned by hot water or steam. This problem compares the heat input to your skin from steam as opposed to hot water at the same temperature. Assume that water and steam, initially at 100∘C, are cooled down to skin temperature, 34∘C when they come in contact with your skin. Assume that the steam condenses extremely fast. The heat capacity of liquid water is c=4190J/(kg⋅K) for both liquid water and steam.
How much heat H1 is transferred to the skin by 25.0 g of steam onto the skin? The latent heat of vaporization for steam is L=2.256

H1 = 63.3 kJ

Explanation:

Given:

ΔL = 2.256 kJ/g

Cp = 4190J/kg⋅K

Steam at 100°C in contact with your skin, condenses to water at 100°C. Therefore,

Q = M × ΔL

= (25.0 g)(2.256 kJ/g)

= 56.4 kJ

This condensed water at 100°C is then cooled to 34°C. The heat involved with this temperature change is;

Q = m × Cp × ΔT

= (25 × 1kg/1000g × 4190 × (100°C - 34°C)

= 6913.5 J

= 6.914 kJ

The total heat H1,

= (56.4 kJ) + (6.9135 kJ)

= 63.3 kJ.

answer: cesare beccaria developed the classical school of criminology with from philosopher jeremy bentham

explanation:

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.