The most common method astronomers use to determine the composition of stars, planets, and other objects is spectroscopy. This process utilizes instruments with a grating that spreads out the light from an object by wavelength. This spread-out light is called a spectrum. Every element has a unique fingerprint that allows researchers to determine what it is made of.
The fingerprint often appears as the absorption of light. Every atom has electrons, and these electrons like to stay in their lowest-energy levels. But when photons carrying energy hit an electron, they can push it to higher energy levels. 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.
The answer to the question given above is letter A. Light
Light is considered a load of the parts of a circuit. <span>The load in a circuit can be
any electrical device that converts electrical energy into other usable forms
of energy such as a <span>light bulb.
>></span></span><span>Energy sources include
batteries and generating stations
>>switch-</span><span>is
used in electric circuits to allow the circuit to be turned on and off.</span>
Answer:
The law is observed in the given equation.
Explanation:
CaCO₃ + 2HCI → CaCI₂ +H₂O + CO₂
In order to find out if the law of conservative mass is followed, we need to <u>count how many atoms of each element are there in both sides of the equation</u>:
- Ca ⇒ 1 on the left, 1 on the right.
- C ⇒ 1 on the left, 1 on the right.
- O ⇒ 3 on the left, 3 on the right.
- H ⇒ 2 on the left, 2 on the right.
- Cl ⇒ 2 on the left, 2 on the right.
As the numbers for all elements involved are the same, the law is observed in the given equation.
Answer:
B. Household ammonia.
Explanation:
NH₃ is a base, so the solution always will be basic.
NH₃ takes the proton from the water. In conclusion we have free OH⁻ in medium, that's why the solution is basic.
NH₃ + H₂O → NH₄⁺ + OH⁻
- HCl + H₂O → H₃O⁺ + Cl⁻
This reaction makes an acid solution, cause the H₃O⁺
- Vinegar is a compound made of acetic acid.
CH₃COOH + H₂O ⇄ H₃O⁺ + CH₃COO⁻
This reaction also makes an acid solution, cause the H₃O⁺
- Pure water makes neutral solution. It is not acid, neither basic.
2H₂O ⇄ H₃O⁺ + OH⁻
The computation for this problem is:
(1.55x10^4 / 1.0x10^3) x 19.8 mm Hg
= 15.5 x 19.88 mm Hg
= 308.14 mm Hg decrease
= 308.14 x 0.05 C = 15.407 deg C
deduct this amount to 100
100 – 15.407 = 84.593 C
ANSWER: 85 deg C (rounded to 2 significant figures)
