All matter is made of particles; these can be single atoms or atoms chemically joined to make molecules. Using this fact, matter can be classified into three broad groups: elements, compounds and mixtures. In an element, all the atoms are of the same type. If more than one type of atom is chemically joined, then a compound has been formed. If more than one type of atom or molecule is contained in the same substance, and the particles aren't chemically joined, this is a mixture.
I feel like the answer would be B. The chair pushes down on the floor becuase the question says when you sit in a chair, your body exerts a downward force on the chair so it would be pushing downward meaning that the chair would also go down making it push onto the floor.
Answer:
fly......................
A Post-and-lintel is a system that uses vertical posts which are separated to
support a horizontal beam.
A Post-and-lintel system is commonly used in architecture and involves the
system where horizontal structures are held by vertical ones with the
presence of spaces between them.
In this scenario, we were told the system uses vertical posts which are
separated to support a horizontal beam which makes Post-and-lintel the
most appropriate choice.
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Answer:
in oil film λ = 303.57 10⁻⁹ m
in the water film λ = 319.55 10⁻⁹ m
Explanation:
When electromagnetic radiation reaches a material, its propagation is by a process that we call absorption and reflection,
when light reaches a surface it has a mass much greater than the mass of the photons (m = 0), therefore there is an elastic collision where the frequency does not change, due to the speed of light in the material medium changes, therefore the only possibility is that the wavelength in the material changes, to maintain the relationship
v = λ f
in the void we have
c = λ₀ f
we divide the two expression
c / v = λ₀ / λ
the refractive index is
n = c / v
n = λ₀ /λ
λ = λ₀ / n
let's calculate
in oil film
λ = 425 10⁻⁹ / 1.40
λ = 303.57 10⁻⁹ m
in the water film
λ = 425 10⁻⁹ / 1.33
λ = 319.55 10⁻⁹
those wavelengths are in the ultraviolet
