Scientists are studying ways to improve the efficiency of solar cells by studying a process called photon upconversion . In this process , the energy of two photons can become combined to form a new photon with an energy equal to the sum of the two combined photons . With this process , abundant infrared radiation can be converted into visible light that can be used by solar celis to produce electricity . Suppose an infrared photon with a wavelength of 853 nm were combined with another infrared photon with a wavelength of 935 nm , what would be the wavelength of the new 'combined photon , in nm ?
Answer:
λ = 4.46 x 10⁻⁷ m = 446 nm
Explanation:
Applying Law of Conservation of Energy in this condition, we will get the following equation:
Total Energy of Combined Photons = Energy of 1st Photon + Energy of 2nd Photon
hc/λ = hc/λ₁ + hc/λ₂
hc/λ = hc(1/λ₁ + 1/λ₂)
1/λ = 1/λ₁ + 1/λ₂
where,
λ = wavelength of combined photon = ?
λ₁ = wavelength of 1st photon = 853 nm = 8.53 x 10⁻⁷ m
λ₂ = wavelength of 2nd photon = 935 nm = 9.35 x 10⁻⁷ m
Therefore,
1/λ = 1/(8.53 x 10⁻⁷ m) + (9.35 x 10⁻⁷ m)
1/λ = (0.1172 x 10⁷ m⁻¹) + (0.1069 x 10⁷ m)
1/λ = 0.2241 x 10⁷ m⁻¹
λ = 1/(0.2241 x 10⁷ m⁻¹)
λ = 4.46 x 10⁻⁷ m = 446 nm
Answer:
446
Explanation:
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Answer:
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Explanation:
Which of the following is an example of erosion?
water freezing inside the cracks of rocks
stalactite and stalagmite formation in caves
plant roots pressing against the sides of rocks
glaciers moving rocks and soil through a valley
Answer:
Glaciers moving rocks and soil through a valley
Explanation:
The definition of Erosion is "the process of eroding or being eroded by wind, water, or other natural agents". Which in turn means the movement of glaciers is causing erosion on the local valley.
the last one
Explanation:
a 500 kilogram sample of substance decays to 125 kilograms over a period of 21.53 years. what is the half life of the sample substance
Answer:
Half life = 10.765 year
Explanation:
Given data:
Mass of sample = 500 Kg
Mass left after 21.53 years = 125 kg
Half life of substance = ?
Solution:
At tome zero = 500 kg
At 1st half life = 500 kg/2 = 250 kg
At 2nd half life = 250 kg/2 = 125 g
Half life:
Half life = time elapsed / number of half life
Half life = 21.53 year/2
Half life = 10.765 year
Which of the following is a valid unit for specific heat?
Explanation:
The specific heat capacity is the amount of heat required to raise the temperature of 1mole or 1kg or 1g of substance by 1k or 1°C
This property is an intensive property of matter and does not depend on the quantity of matter present.
Some of the unit of specific heat are;
J/g°C, J/kg°C, J/mol°C, J/molK , Cal/g°C
You complete titration of 15.0ml of unknown acid with 14.16ml of 1.25 M NaOH. What’s the molar it’s of the unknown acid? Assume the acid is monoprotic 1 mole of acid reacts with 1 mole of base.
The molarity of the unknown acid : 1.18 M
Further explanationTitration is a procedure for determining the concentration of a solution by reacting with another solution that is known to be concentrated (usually a standard solution). Determination of the endpoint/equivalence point of the reaction can use indicators according to the appropriate pH range
Titration formula
M₁V₁n₁=M₂V₂n₂
monoprotic acid⇒n₁=1
NaOH monoprotic base⇒n₂=1
[tex]\tt M_1\times 15=1.25\times 14.16\\\\M_1=1.18~M[/tex]
Compare and contrast how observations and results can be used to
support a conclusion to an experiment.
Answer:
by statistical analyses, especially by determining the p-value
Explanation:
In general, observations and results obtained from experimental procedures are subjected to a statistical test to check the robustness of the working hypothesis. The p-value is the most widely used statistical index in order to test such observations and results. The p-value is the statistical probability of obtaining extreme observed results when the null hypothesis is considered correct. A p-value lesser than 0.05 generally is considered statistically significant and then the null hypothesis can be rejected. In consequence, a very low p-value (which is obtained by statistical analysis of the observations and results), indicates that there is strong evidence in support of the alternative hypothesis.
Match the terms with their definitions
Frequency, Amplitude, Crest, Wavelength, Medium, Trough
Matter distributed by energy
Highest point of transverse wave
Lowest point of transverse wave
Distance between midpoint of wave and crest
Distance traveled in one wave cycle
Number of waves that pass per second
(from brainpop waves.) PLease HeLP (Worth 25 POINTS)
Answer:
amplitude= distance between midpoint of a wave and crest
crest= highest point of transverse wave
wavelength= distance traveled in one wave cycle
medium= matter distributed by energy
trough=lowest point of transverse wave
frequency=number of waves that pass per second
Explanation:
A wave is a dynamic perturbation of one or even more quantities that propagates in a specific medium.
What is wave?A wave is a dynamic perturbation of one or even more quantities that propagates in physics, mathematics, or related sciences. When waves oscillate frequently around an equilibrium position at a certain frequency, they are said to be periodic. A traveling wave is one in which the whole waveform moves inside one direction; in contrast, a standing wave is one in which two periodic waves are overlaid and move in the opposing directions.
In a wave form, there are some points in which the wave amplitude seems reduced or even zero, and these positions have null vibration amplitudes. A wave equation or perhaps a one-way wave equation describing single wave propagation inside a specific direction is frequently used to describe waves.
amplitude= distance between midpoint of a wave and crest
crest= highest point of transverse wave
wavelength= distance traveled in one wave cycle
medium= matter distributed by energy
trough=lowest point of transverse wave
frequency=number of waves that pass per second
Therefore, a wave is a dynamic perturbation of one or even more quantities that propagates
To know more about wave, here:
https://brainly.com/question/13779567
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Question 24 (3 points)
Choose the element below that has correct information about the number of energy
levels/orbitals: (Use a period table to answer this question).
Lithium (Li) has one energy level
Sodium (Na) has three energy levels
Potassium (K) has three energy levels
Fluorine (F) has seven energy levels.
Answer:
sodium
Explanation:
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Answer:
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Explanation:
Answer:
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Explanation:
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Which subatomic particles are stolen and/or shared when atoms bond together during a chemical reaction?
A. protons
B. Subatomic particles are not involved in atomic bonding
C. neutrons
D. electrons
Answer:
D. electrons
Explanation:
Chemical bonds occur as a result of electrons (negatively-charged subatomic particles) being transferred among atoms. The transfer happens when electrons are being stolen or shared from an atom to another. The reason behind this is because atom's atomic shells are naturally inclined to be full. Thus, if one atom has extra electrons, that atom will most likely share his electrons to another atom lacking in it.
Comprehensive studies have shown that forensic scientists should look for between 8 to 16 points to establish identification
based on fingerprints.
true or false
Answer:
FALSE
Explanation:
right answer on plato:)
Question 23 (1 point)
A student is given an object with a mass of 14.8 grams. When placed into a
graduated cylinder the water level rises from 25.0 mL to 34.7 mL.
What is the density of the object and would you expect it to float or sink in the
graduated cylinder if water has a density of 1.00 g/mL? Show all of your work.
Answer:
d = 1.53 g/mL
Object will sink into water
Explanation:
Given data:
Mass of object = 14.8 g
Initial volume of water = 25.0 mL
Final volume after adding object = 34.7 mL
Density of object = ?
Density of water = 1.00 g/mL
Solution:
Volume of object = Total volume - volume of water
Volume of object = 34.7 mL - 25.0 mL
Volume of object = 9.7 mL
Density of object;
d = mass/volume
d = 14.8 g / 9.7 mL
d = 1.53 g/mL
The density of water is 1.00 g/mL which means object is heavier than water thus object will sink into the water. The object with density less than water are float in it.
What is the number of neutrons in Hydrogen, O (A= 1, Z= 1)?
Answer:
Explanation:
Hydrogen has 1 proton and one nuetron
Oxygen has 8 protons nad 8 neutrons
Which of the following elements would you expect to lose one electron? Select all that apply.
a. sodium
b. chlorine
c. Fluorine
d. Potassium
Answer:
Potassium, sulfur, fluorine, barium
The elements that will lose one electron are:
a. sodium
d. Potassium
What will happen when an element looses one electron?An element in its natural state has an equal number of protons and electrons, giving it a net charge of zero; however, when an element loses an electron as part of a chemical reaction it becomes positively charged, or oxidized.
Out of the given options, sodium and potassium looses one electron and attains a positive charge leading to the formation of cation. While Fluorine and chlorine gains one electron and attains a negative charge leading to the formation of anion.
Thus, correct options are a and d.
Find more information about Cations here:
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During the reaction: Mg(s) + CuSO4(aq)
es)
MgSO4(aq) + Cu(s), what changes occur to magnesium?
A)Its oxidation number changes from +2 to 0 and it is reduced.
B)Its oxidation number changes from 0 to +4 and it is reduced.
C)Its oxidation number changes from 0 to +2 and it is oxidized.
D)Its oxidation number changes from +2 to +4 and it is oxidized.
Answer:
C
Explanation:
I did it on usatestprep
What does a detergent do to water to help the bubbles last
Answer:
Detergent lowers the surface tension of water enough so that bubbles can form. ... Glycerin makes stronger, longer-lasting bubbles, but corn syrup is often substituted in bubble solutions because it is cheaper.
Explanation:
Hope this helps.
It reduces the [surface] tension of the water to form bubbles
An atom of oxygen has six valence electrons. In nature, oxygen is a diatomic molecule and is usually found in the form O2. Why would one atom of oxygen want to bond with another one?
A) When the oxygen atoms bond together, they become ionized.
B) The transfer electrons to each other so they both have a full shell of valence electrons.
C) When oxygen atoms share electrons the outer shell of electrons is filled and each atom becomes more stable.
D) A single atom of oxygen is very stable and simply joins with another oxygen in order to destabilize both of them.
Answer:
I think the answer is B
Explanation:
Answer:
oxygen atom is a unstable atom so it gets attached to other oxygen atom sharing valance electrons to become stable
C is the right ans
According to Boyle’s law, when the pressure of a gas increases at constant temperature, its volume
Answer:
the volume increases
Explanation:
Which statement about the relationship between laws, hypotheses, and theories is true?
The density of magnesium is 1.7/cm3, and the density of iron is 7.9g/cm3. Consider a block of iron with a mass of 819 g. What is the mass of a block of magnesium that has the same volume as the block of iron?
5. You add 11.00 mL of 0.800 M NaOH to 50.00 mL of pure water, and to this mixture you then add 3.00 mL of 0.200 M HCl. What will be the pH of the resulting solution
Answer:
pH = 13.11
Explanation:
NaOH reacts with HCl to produce H2O and NaCl. pH depends of this reaction. The reactant in excess determine the pH of the solution:
NaOH + HCl → H2O + NaCl
1 mole of NaOH reacts with 1 mole of HCl
To determine limiting reactant we need to find moles of each reactant:
Moles NaOH:
0.011L * (0.800 mol / L) = 0.0088 moles NaOH
Moles HCl:
0.003L* (0.200mol / L) = 0.0006 moles HCl
That means limitng reactant is HCl and moles in excess of NaOH are:
0.0088moles NaOH - 0.0006 moles = 0.0082 moles NaOH =
0.0082 moles OH⁻
In 11.00mL + 50.00mL + 3.00mL = 64.00mL = 0.06400L
[OH-] = 0.0082 moles OH- / 0.064L = 0.1281M OH-
pOH = -log [OH-] = 0.89
pH = 14 - pOH
pH = 13.11Which of the following aspects of biotechnology is not considered to be a moral or ethical issue
The question is incomplete, the complete question is;
Which of the following aspects of biotechnology is Not considered to be a moral or ethical issue?
a.research and testing on animals
b.cloning living material
c.reducing research cost
d.damaging the environment
Answer:
c.reducing research cost
Explanation:
Ethical issues arise when a particular course of action is at odds with the generally acceptable moral standard in the society.
Research and testing on animals is contested as an ethical issue by animal rights activists.
Cloning living material is prohibited among some sections of society and is also being contested as an ethical issue.
Damaging the environment the environment owing to biotechnology research is generally regarded as an ethical issue.
However, reducing research cost is highly acceptable in any research. It does not pose an ethical issue.
What did J.J. Thomson discover about electrons?
a
Atoms are indivisible.
b
Electrons are inside the nucleus of an atom.
c
Electrons are scattered in a positively charged atom.
d
Atoms of the same element have the same properties.
The answer is D
Brainliest?
Are bonds broken or formed, throughout each phase change present on a heating
curve?
Answer:
During a phase change no chemical bonds are broken. Atoms are not rearranged because a phase change is a physical change rather then a chemical change. However, intermolecular forces are almost entirely removed from the liquid since the intermolecular forces are what cause the liquid to be a liquid.
Explanation:the nature of the intermolecular forces (IMF) will not change when the state changes from solid to liquid, however, the number of IMF changes.
Which of the following practices can help control erosion?
recycling paper
harvesting earlier
tree removal
contour plowing
Answer:
Contour plowing
Explanation:
Contour plowing is one of the activity that can help control the rate of erosion in a given place.
Erosion is the washing away of the layer of the earth. In agricultural practices, rich top soil can be eroded if adequate measures are not taken. Contour plowing is the process of planting along the sides of a ridge following the contour patterns. This helps to break down slopes and reduce erosion.all matter has physical and chemical properties. These properties can be used to identify the type of matter. Which of these statements describe a physical property?
Explanation:
Physical properties of matte tells us everything about a substance when no change is occurring to its constituents.
Such properties are best observed with our senses. Also, physical properties can be observed using equipment in the laboratory or some apparatus.
Examples of these properties are state of matter, color, odor, taste, texture, hardness, solubility in water, melting point, boiling point, density, viscosity and spectroscopic patterns.Sugar(C6H1206) and salt( NaCl) are examples of
Answer:
compounds
Explanation:
It is a substance formed when two or more. When the elements are joined, the atoms lose their individual properties and have different properties from the elements they are composed of.
Answer:
Brain big big brain
Explanation:
Biggest brain small brain Big brain big stonks
A food item that is left out of the refrigerator turns brown and forms bubbles and gas. What are the signs that this is a chemical reaction?
Check all that apply.
Heat is produced.
Heat is absorbed.
Bubbles appear.
A precipitate forms.
The color changes.
Answer:
C & E
Explanation:
Which number represents an acidic pH, 4 or 9? _______ Numerical Answers Expected! Answer for Blank 1:
Answer:
4
Explanation:
pH scale of acidic is 4.
Answer: 4
Explanation: