What two things do astronomers need to know about a star in order to calculate its luminosity or absolute magnitude? A.color and size B.color and distance C.distance and brightness D.size and distance
(đ) is answer of question.
Explanation:
However, the brightness of a star depends on its composition and how far it is from the planet. Astronomers define star brightness in terms of apparent magnitude — how bright the star appears from Earth — and absolute magnitude — how bright the star appears at a standard distance of 32.6 light-years, or 10 parsecs.
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Astronomers measures the luminosity of stars by determining the magnitude of brightness and distance from earth.Thus option C is correct.
What is luminosity?Luminosity of a star is the total amount of energy radiated by them to a distance. The luminosity vary from star to star based on the distance to them.
Luminosity is basically measured in terms of brightness as observed from the earth. Stars will make a group in certain shapes and certain number called constellation. The overall brightness can be then higher for each constellation.
Astronomers define the brightness of stars by the apparent distance from the earth whereas the absolute magnitude is defined is terms of standard distance of 32.6 light years. Hence, the option C based on distance and brightness is correct.
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plz help fast lot of points.
Answer:
The one at the top: cuticle
The highest line on the right side: palisade layer
The third line on the left: chloroplast
The line near phloem: vein
The line at the bottom: stomata
Entirely on the attachment.
Explanation:
No need.
Help me out with this question , can someone give me the answer ?
:((
Answer:
I pretty usre they cause erosion wich makes fresh soil so B.
Explanation:
isotopes Mg-24,Mg-25 and Mg-26 has natural abundance of 79.0%,10.0% and 11.0%. Calculate the relative atomic mass for isotopes Mg-24,Mg-25 and Mg-26.
Please help me with with this question....
Ryan and Abigail are conducting an experiment. They place six ice cubes into a beaker and find the combined mass. They allow the ice cubes to melt and find the combined mass of the beaker and the liquid water.
A
A
Before
After
What can the students expect to be true about the two masses?
The mass of the ice cubes will be greater because solids are more dense.
The mass of the ice cubes will be greater because they took up more space in the beaker.
The mass of the ice cubes and the water will be equal because the same amount of matter is in the beaker
The mass of the ice cubes and the water will be equal because their particles have the same amount of energy
B
c
С
D
The mass of the ice cubes and the water will be equal because the same amount of matter is in the beaker.
Matter is anything that has mass and occupy space. All substances are composed of matter. According to the law of conservation of mass, matter can neither be created nor destroyed but can be converted from one form to another.
Since mass is the quantity of matter in a substance, the mass of the ice cubes and the water will be equal because the same amount of matter is in the beaker.
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A scientist studying the properties of two different gases recorded this data. If the scientist wants to study gas samples A and B at
standard temperature and pressure (STP), what must she do before continuing experimentation?
Answer:
C. Decrease the pressure of Gas A and increase the temperature of Gas B.
Explanation:
The values for standard temperature and pressure (STP) are zero degrees Celsius and one atmosphere. Since the temperature of gas A is higher than zero degrees, it will have to be reduced. Since the pressure of gas B is less than one atmosphere, it will have to be increased.
A valence electron is
a) any electron in the highest energy level of an atom
b) the electron closest to the nucleus of an atom
c) any electron that does not take part in chemical bonding
d) the electron that is gained when a cation is formed
The distance from one crest to the next crest is ____
Answer:
Wavelength is the distance from one crest to another, or from one trough to another, of a wave (which may be an electromagnetic wave, a sound wave, or any other wave). Crest is the highest point of the wave whereas the trough is the lowest.
Explanation:
Hope this helps!
Answer:
Wavelength!
Explanation:
Hope this helps, please give me brainliest. ;)
Which element in the list is the most reactive?
C
Ba
S
Cs
Answer:
Cs
Explanation:
This element is the farthest right, and lowest meaning that the reactivity of it is very high.
1. valence electrons and electronegativity
2. Both reactivity and electronegativity decrease down a group.
3. Electronegativity decreases down a group, and reactivity increases down a group.
4. The number of valence electrons increases from left to right.
5. Cs
{quizlet: captncrun}
Distinguish the endothermic and exothermic energy changes associated with ionic bond formation, and relate it to stability
Answer:
When ionic compounds are formed, energy is released which is exothermic energy. If the energy released during bond formation is reabsorbed, the ionic bond holding the positive ions and negative ions together will break apart which is endothermic energy.
Explanation:
The formation of an ionic crystal lattice from its constituent ions is an exothermic process.
Endothermic changes are energy changes in which energy is absorbed while exothermic energy changes are those energy changes in which energy is evolved.
During the formation of an ionic bond, the metal looses electron(s). This is an endothermic process. The nonmetal accepts electrons. This is an exothermic process.
When the ionic crystal is formed, energy is given out because the energy of the lattice is less than the energy of the isolated ions. This heat change is exothermic.
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what is the trend for atomic radii across the periods and down the group?
Answer:
So, in general, atomic radius decreases across a period and increases down a group. Across a period, effective nuclear charge increases as electron shielding remains constant.
Explanation:
Moving from left to right across a period, the atomic radius decreases. The nucleus of the atom gains protons moving from left to right, increasing the positive charge of the nucleus and increasing the attractive force of the nucleus upon the electrons.
Have a happy day! <3Miss Hawaii
How much effort force would you use to lift a 300 kg weight with a fixed pulley system?
Answer:
It would take 150 kg to lift the load
Explanation:
what additional reaction product would result if naoh was used as a base in this reaction instead of k2co3?
Answer:
What reaction product would result if NaOH was used as a base in this reaction instead of K2CO3? If sodium hydroxide was used as the base of the reaction, then the reaction product formed would be an ethyl alcohol because it would undergo a hydrolysis reaction with addition of iodoethane
The entire carbonation reaction demonstrates how potassium carbonate (K2CO3) combines with water and carbon dioxide to create potassium bicarbonate (KHCO3) when exposed to combustion flue gases at low temperatures (40 to 80 °C) (Reaction 1)
What takes place when K2CO3 and water interact?In an extremely violent and exothermic reaction, potassium carbonate splits into potassium and carbonate ions when it interacts with water. When the ions interact, potassium oxide and carbonic acid are created.
K2CO3 come from : Potassium carbonate is a common ingredient in the manufacture of soap and glass. Additionally, it serves as a light drying agent. This substance is used as a buffering agent in numerous wine making procedures. Another usage for potassium carbonate is as a fire extinguisher.
K2CO3 created : Commercially, potassium carbonate is made by reacting potassium hydroxide with carbon dioxide:
2 KOH + CO2 = K2CO3 + H2.
K2CO332H2O sesquihydrate crystallizes from the solution ("potash hydrate").
The anhydrous salt is produced by heating this solid at 200 °C (392 °F).
It disintegrates into K2O+CO2 around 1200 C. (allreaction)
By converting carbonate into carbon dioxide and water, potassium carbonate can act as a base by forming potassium hydroxide.
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how many feet are equal to 25.51 dm
Answer:
8.3 feet
hope this helps! <3
What is the SI base unit of temperature?
Answer:
Kelvin
Explanation:
What is the wavelength of a radio wave that has a frequency of 9.40 X 10^8Hz?
3.1
(b) A student states, "When the alcohol sample was at a temperature of 500 K, all the particles
were moving faster than any of the particles were moving at 400 K." Do you agree or disagree
with this student's statement? Justify your answer.
B
I
Submit
514
alel
(c) Using boxes like the ones below, draw three particle diagrams representing the sample of
alcohol cooling in this experiment. The diagrams should represent the sample at 3 minutes, 12
minutes, and 17 minutes.
Sign out
09:50
The kinetic energy of particles depends on temperature. As temperature increases, the kinetic energy of particles increases.
Temperature is defined as a measure of the average kinetic energy of the molecules of a substance. The higher the temperature of a substance the greater its kinetic energy.
From the foregoing, when the temperature is increased from 400K to 500K, greater kinetic energy is imparted to the molecules of the substance hence they move faster according to the kinetic theory of matter.
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A horse runs 1 km in 15 s. What is the average speed
The average speed of the horse for the entire motion is 66.67 m/s.
The given parameters;
distance traveled by the horse, d = 1 km = 1,000 mtime of motion of the horse, t = 15 sThe average speed of the horse is calculated by dividing the total distance traveled by the horse by the time of motion.
The average speed of the horse is calculated as follows;
[tex]average\ speed = \frac{distance}{time} \\\\average\ speed = \frac{1000 \ m}{15 \ s} = 66.67 \ m/s[/tex]
Thus, the average speed of the horse for the entire motion is 66.67 m/s.
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Someone pls help me I will make you brain
Answer:
a
Explanation:
Someone pls help me I will make you you brain
Answer:It’s cyclone movement
Explanation:
what is the maximum number of electrons in an atom n=4 l=1 ml=0
Answer:
18 electrons
Explanation:
when l=1, this tell you that it is "p sub shell"
Con que otras materias se relaciona la química
Answer:
Fisica, Astronomia, Biologia
Explanation:
con esta relacion entre ellas se puede explicar y comprender fénomenos de la naturaleza.
a bronsted lowry acid is defined as a substance that
Answer:
that donate H+ ion.
Explanation:
hope this helps :)
Physics have been taking the Hippocratic Oath for more than 2,000 years. Among other things, to Serie doctors who take the oath promise to uphold doctor-patient confidentiality. Why do you think this is an ethical issue?
Answer:
Physicians and it is ethical because they promise to help
Explanation:
which alkyl halide reacts fastest with trimethylamine in sn2 reaction?
Structure V reacts fastest with trimethylamine in SN2 reaction. Owing to less steric crowding in the transition state and ease of cleavage of the R - I bond
The question is incomplete, the complete question is shown in the image attache to this answer.
SN2 reaction is a type of nucleophilic reaction in which the nucleophile attacks the substrate from the reverse side. This is a synchronous reaction because the leaving group departs as the entering group attacks simultaneously in a hypervalent transition state.
SN2 reaction is favored by structure V owing to less steric crowding in the transition state and the easy of cleavage of the R - I bond. Hence, structure V reacts fastest with trimethylamine in SN2 reaction.
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5. A football field is about 100 meters long. If it takes a person 20 seconds to run its length, how fast (what speed) were they running?
Answer:
Speed, v = 5 m/s
Explanation:
The length of the football field, l = 100 m
the person takes 20 seconds to run its length
v=
t
d
v=
20 s
100 m
v=5 m/s
which scenario supports the ""one gene–one enzyme"" hypothesis of metabolic disease causation?
The scenario that supports the "one gene-one enzyme" hypothesis of metabolic disease causation is Phenylketonuria (PKU). This disease (PKU) is caused by the failure to produce a functional variant of an enzyme.
Phenylketonuria (PKU) is a metabolic inherited disorder associated with a decreased metabolism of the amino acid phenylalanine.
PKU is caused by a mutation in the gene responsible for encoding a key enzyme needed to break down phenylalanine.
Untreated PKU may lead to diverse health problems which include brain damage, intellectual disability, seizures, mental disorders, etc.
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Someone pls help me I will make you you brain
Answer:
A
Explanation:
it's Conventional Movement
Give the number of the sample bottle that contains a substance that would be used in
each situation.
1.
Plumbing
5.
Computer chips
2.
Flavoring Food
6.
Edible Cooking Ingredient
3.
Crafts
7.
Edible Cooking Ingredient
For a headache
8.
Edible Cooking Ingredient
to o N O
4.
Beth measured her brand new figurine to be
17.550 cm tall. However, the manufacturer
claims that it is 17.260 cm tall. What is the
percent error in Beth's measurement?
A 1.68%
B
1.65%
Answer: A
Explanation: I just answered mine