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07. How do scientists use spectroscopy (the study of light frequencies released

Vera_Pavlovna [14]

Every element is able to be recognized individually in many different ways. A very easy and common way is using light absorption also known as spectroscopy. Every atom has electrons, and these electrons like to stay in their lowest-energy configuration. However, when photons collide with an electron it can increase it to a higher energy level.. This is absorption, and each element’s electrons absorb light at specific wavelengths related to the difference between energy levels in that atom. But the electrons want to return to their original levels, so they don’t hold onto the energy for long. When they emit the energy, they release photons with exactly the same wavelengths of light that were absorbed in the first place. An electron can release this light in any direction, so most of the light is emitted in directions away from our line of sight. Therefore, a dark line appears in the spectrum at that particular wavelength.

Because the wavelengths at which absorption lines occur are unique for each element, astronomers can measure the position of the lines to determine which elements are present in a target. The amount of light that is absorbed can also provide information about how much of each element is present.

8 0

3 years ago

How did the atomic theory develop and change

IgorC [24]

Explanation:

Early Atomic theory

Although the idea of the atom was first suggested by Democritus in the fourth century BC, his suppositions were not useful in explaining chemical phenomena, because there was no experimental evidence to support them. It was not until the late 1700's that early chemists began to explain chemical behavior in terms of the atom. Joseph Priestly, Antoine Lavoisier, and others set the stage for the foundation of chemistry. They demonstrated that substances could combine to form new materials. It was the English chemist, John Dalton, who put the pieces of the puzzle together and developed an atomic theory in 1803.

Dalton's atomic theory contains five basic assumptions:

All matter consists of tiny particles called atoms. Dalton and others imagined the atoms that composed all matter as tiny, solid spheres in various stages of motion.

Atoms are indestructible and unchangeable. Atoms of an element cannot be created, destroyed, divided into smaller pieces, or transformed into atoms of another element. Dalton based this hypothesis on the law of conservation of mass as stated by Antoine Lavoisier and others around 1785.

Elements are characterized by the weight of their atoms. Dalton suggested that all atoms of the same element have identical weights. Therefore, every single atom of an element such as oxygen is identical to every other oxygen atom. However, atoms of different elements, such as oxygen and mercury, are different from each other.

In chemical reactions, atoms combine in small, whole-number ratios. Experiments that Dalton and others performed indicated that chemical reactions proceed according to atom to atom ratios which were precise and well-defined.

When elements react, their atoms may combine in more than one whole-number ratio. Dalton used this assumption to explain why the ratios of two elements in various compounds, such as oxygen and nitrogen in nitrogen oxides, differed by multiples of each other.

John Dalton's atomic theory was generally accepted because it explained the laws of conservation of mass, definite proportions, multiple proportions, and other observations. Although exceptions to Dalton's theory are now known, his theory has endured reasonably well, with modifications, throughout the years.

7 0

3 years ago

Se lanza una bala con una velocidad inicial de 200 m/s y con un ángulo de inclinación de 30º respecto a la horizontal. Si se con

puteri [66]

Answer:

El alcance de la bala es 3464,1 m.

Explanation:

El alcance de la bala se puede calcular como sigue:

$y = y_{0} + tan(\theta)*x - \frac{g}{2}*\frac{x^{2}}{(v_{0}cos(\theta))^{2}}$

En donde:

y: es la altura final = 0

$y_{0}$ : es la altura inicial = 0

x: es el alcance

θ: es el angulo respecto a la horizontal = 30°

$v_{0}$ : es la velocidad inicial = 200 m/s

g: es la gravedad = 10 m/s²

Entonces, tenemos:

$y = y_{0} + tan(\theta)*x - \frac{g}{2}*\frac{x^{2}}{(v_{0}cos(\theta))^{2}}$

$x = \frac{2tan(\theta)*(v_{0}cos(\theta))^{2}}{g} = \frac{2tan(30)*(200 m/s*cos(30))^{2}}{10 m/s^{2}} = 3464,1 m$

Por lo tanto, el alcance de la bala es 3464,1 m.

Espero que se te sea de utilidad!

8 0

3 years ago

. Draw a Cartesian coordinate system on a sheet of paper. On this Cartesian coordinate system, draw each vector to scale, starti

Triss [41]

Answer:

a) the first vector has magnitude 58 cm and the angle is 15 measured clockwise from the positive side of the x-axis

b) the second vector, the magnitude is 55.7 cm and the angle is 35 half from the negative side of the x-axis in a clockwise direction

c) the magnitude is 54.2 cm with an angle of 18 measured counterclockwise from the x-axis

Explanation:

For this exercise we draw a Cartesian coordinate system in this system: East coincides with the positive part of the x-axis and North with the positive part of the y-axis.

a) the first vector has magnitude 58 cm and the angle is 15 measured clockwise from the positive side of the x-axis

b) the second vector, the magnitude is 55.7 cm and the angle is 35 half from the negative side of the x-axis in a clockwise direction

c) the magnitude is 54.2 cm with an angle of 18 measured counterclockwise from the x-axis

In the attachment we can see the representation of the three vectors

8 0

2 years ago

What do scientists use to determine the temperature of a star?

Vera_Pavlovna [14]

Thermal Imaging. Hope it helps.

4 0

3 years ago

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