Answer: spectroscopy
Spectroscopy is the separation of the light in the different wavelengths and spectrophotometry measures the intensities of the different components of the light to get the composition of substances.
It occurs when energy is supplied or withdrawn :)
During the phase transition vapour --> liquid water, the temperature of the water does not change; the molecules of water release heat and the amounf of heat released is equal to

where
m is the mass of the water

is the latent heat of evaporation.
For water, the latent heat of evaporation is

, while the mass of the water is

so, the amount of heat released in the process is
Answer:
Mass of the steel cube = 7800 kg
Volume of the steel = 1.025 cubic centimetre
Explanation:
Given:
The density of the steel = 7.8
Side of the cube = 12 cm
<u>(1)The mass of steel cube :</u>
We know that,

We are given with density and sides of the cube
then volume of the cube
=
= 
= 1000 cubic centimetre
Now


mass = 7800 kg
<u>(2)volume of steel:</u>
Given the mass = 8 kg

Substituting the values


volume = 1.025 cubic centimetre