A Carnot Engine operates between two heat reservoirs. The cold reservoir is maintained at 20.0 °C. What temperature must the hot reservoir be at in order for the efficiency of the engine to be 20.0 %?

Answer:

[tex]80\; {\rm m\cdot s^{-1}}[/tex].

Explanation:

The frequency [tex]f[/tex] of a wave is the number of cycles completed in unit time ([tex]1\; {\rm s}[/tex] in this example.) In this question, [tex]f = 40\; {\rm s^{-1}}[/tex] ([tex]1\; {\rm Hz} = 1\; {\rm s^{-1}}[/tex]) means that the wave would complete [tex]40[/tex] cycles in every [tex]1\; {\rm s}[/tex].

The wavelength [tex]\lambda[/tex] of a wave is the distance the wave travels in each cycle. It is given that [tex]\lambda = 2\; {\rm m}[/tex].

The goal is to find the wave speed, which is the distance that this wave travels in unit time ([tex]1\; {\rm s}[/tex].)

In this question, it is given that [tex]\lambda = 2\; {\rm m}[/tex] and [tex]f = 40\; {\rm s^{-1}}[/tex]. Thus, this wave would travel a total of [tex]40\, (2\; {\rm m}) = 80\; {\rm m}[/tex] for the [tex]40[/tex] cycles completed in each unit time of [tex]1\; {\rm s}[/tex] ([tex]\lambda = 2\; {\rm m}[/tex] for each cycle.) The speed of this wave would be [tex]80\; {\rm m\cdot s^{-1}}[/tex].

Formally, the speed [tex]v[/tex] of this wave can be found by multiplying the wavelength [tex]\lambda[/tex] of this wave by its frequency [tex]f[/tex]:

[tex]\begin{aligned}v &= \lambda\, f \\ &= (2\; {\rm m})\, (40\; {\rm s^{-1}) \\ &= 80\; {\rm m\cdot s^{-1}}\end{aligned}[/tex].

The top surface of the oil on that side of the tube is 0.6 times higher than the surface of the water on the other side of the tube.

The principle of hydrostatics, also known as Pascal's principle, states that when an external pressure is applied to a fluid in a container, that pressure is transmitted uniformly in all directions within the fluid, regardless of the shape or volume of the container. In other words, the pressure applied to a confined fluid will be distributed evenly throughout the fluid and will not change in magnitude at any point within the fluid. This principle is important in a number of applications, such as hydraulic systems, which use fluids to transmit force and pressure from one point to another. It is also used to explain how liquids exert pressure on the walls of their container and how objects can float or sink in fluids.

We can use the principles of hydrostatics to solve this problem. Let's call the height difference between the two water surfaces h. We can assume that the oil completely covers the water on one side of the tube and does not mix with it, so the oil and water form two separate liquid columns with a common interface. Let's call the height difference between the oil and water surfaces on the same side of the tube H.

The pressure at any given point in a fluid depends only on the depth of that point below the surface of the fluid and the density of the fluid. Since the two water columns are at the same height, they experience the same pressure from the atmosphere. Similarly, the two oil columns experience the same pressure from the atmosphere.

Now consider a point on the interface between the oil and water on the same side of the tube. This point is at a depth of h+H below the water surface on the other side of the tube, so the pressure at this point is greater than atmospheric pressure by an amount equal to the product of the density of water, the acceleration due to gravity, and the total depth (h+H):

P = Patm + ρwatergh

where P is the pressure at the interface, Patm is atmospheric pressure, ρwater is the density of water, g is the acceleration due to gravity, and h+H is the total depth.

Similarly, the pressure at this point is less than atmospheric pressure by an amount equal to the product of the density of oil, the acceleration due to gravity, and the depth of the oil column (H):

P = Patm - ρoilgH

Since the interface between the oil and water is at the same pressure, we can equate these two expressions for P:

Patm + ρwatergh = Patm - ρoilgH

Solving for H, we get:

H = h(ρwater/ρoil)

Substituting the given values, we get:

H = 0.6h

Therefore, the top surface of the oil on that side of the tube is 0.6 times higher than the surface of the water on the other side of the tube.

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The speed of the waves can be expressed to two significant figures as 0.2 m/s. The unit for this expression is meters per second (m/s).

A wave crest is the highest point of a wave. It is the top of the wave, where the wave is moving most up and away from the equilibrium position. It is the point of highest amplitude (height) of the wave and is followed by a wave trough, which is the lowest point of the wave.

The speed of the waves can be calculated using the formula speed = distance over time.

We know the distance between wave crests is 9.0 m and the time it takes for 12 waves to pass the boat is 45 s. Therefore, the speed of the waves can be calculated as:

Speed = 9.0 m / 45 s

Speed = 0.2 m/s

The speed of the waves can be expressed to two significant figures as 0.2 m/s. The unit for this expression is meters per second (m/s).

This calculation shows that the speed of the waves passing the boat is 0.2 m/s. This speed can be further broken down into how many meters the waves travel in one second if necessary.

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Answer:

correlation is defined as the statistical association between two variables

Explanation:

a correction exits between two variables when one of them is related to the other in some way

Humans would need a breathable environment like that on Earth in the living section of a colony on Venus in order to survive. Nitrogen, oxygen, and trace amounts of other gases, such as carbon dioxide, make up the majority of the atmosphere on Earth.

The clouds are made of sulfuric acid, and the atmosphere is primarily carbon dioxide, the same gas that causes the greenhouse effect on Venus and Earth. And the heated, high-pressure carbon dioxide acts corrosively at the surface.

For instance, compared to Earth, which has 99% nitrogen and oxygen in its atmosphere, Venus and Mars both contain more than 98% carbon dioxide and nitrogen.

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a) The time after the release of the first stone that the second stone hits the water is 2.0 s.

b) 15.7 m/s is the initial speed of the second stone.

c)  The speed of the first stone as it hits the water is 15.7 m/s.

d) The speed of the second stone as it hits the water is 28.2 m/s.

Velocity is a vector quantity that measures both the speed and direction of an object's motion. It is equal to the rate of change of an object's position with respect to time. Velocity is usually represented by the symbol v and is measured in meters per second (m/s).

a) The time between first and second stone's release is 1.0 s. Since the time of release of first stone and the time of splash of both stones are same, the time between the release of second stone and the splash of both stones is 1.0 s.

Thus, the time after the release of the first stone that the second stone hits the water is 2.0 s.

b) The initial speed of the second stone can be calculated using the equation of motion,

v² = u² + 2as

where v is the final velocity, u is the initial velocity, a is the acceleration due to gravity (9.8 m/s²), and s is the displacement.

Substituting the values,

v² = (1.7)² + 2(9.8) * 59

v = 15.7 m/s

c) The speed of the first stone as it hits the water can be calculated using the equation of motion,

v² = u² + 2as

where v is the final velocity, u is the initial velocity, a is the acceleration due to gravity (9.8 m/s²), and s is the displacement.

Substituting the values,

v² = (1.7)² + 2(9.8) * 59

v = 15.7 m/s

d) The speed of the second stone as it hits the water can be calculated using the equation of motion,

v² = u² + 2as

where v is the final velocity, u is the initial velocity, a is the acceleration due to gravity (9.8 m/s²), and s is the displacement.

Substituting the values,

v² = (15.7)² + 2(9.8) * 59

v = 28.2 m/s

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The above has to do with the study of the earth's lithospheric plates. See the attached image and the explanation below.

The movement of lithospheric plates is a geological process that occurs due to the motion of hot, molten material in the Earth's mantle. The lithosphere, which is the rigid outer layer of the Earth's surface, is divided into several large plates that move relative to each other.

These movements are caused by the convection of material in the mantle and the forces that arise at the boundaries between the plates.

There are three main types of plate boundaries: divergent, convergent, and transform. Divergent boundaries occur where plates move apart from each other, creating new oceanic crust. Convergent boundaries arise where plates collide, leading to subduction, volcanic activity, and the formation of mountains. Transform boundaries occur where plates slide past each other.

The movement of lithospheric plates gives rise to various geological phenomena, such as earthquakes, volcanic activity, and the formation of mountain ranges and ocean basins.

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The researcher did not find strong evidence to support the idea that job applicants with popular names are viewed more favorably than equally qualified applicants with less popular names.

It sounds like the researcher conducted an experiment to investigate whether job applicants with popular names are viewed more favorably than equally qualified applicants with less popular names.

Based on the information provided, the researcher found that the differences in the evaluations of the applicants by the two groups were not significant at the .001 level.

The factors that play an important role in the hiring process for a job:

(1) Qualifications and experience: Employers typically look for candidates who possess the necessary qualifications and experience for the job. This includes education, training, certifications, and work experience.

(2) Skills and abilities: Employers also consider a candidate's skills and abilities related to the job. These may include technical, interpersonal, communication, and problem-solving skills.

(3) Personal characteristics: Personal characteristics, such as motivation, work ethic, and adaptability, can also play a role in the hiring process. Employers may look for candidates who demonstrate a positive attitude, a willingness to learn, and the ability to work well with others.

(4) Fit with company culture: Companies may also consider whether a candidate fits with their company culture, values, and mission. This can include factors such as teamwork, creativity, and innovation.

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Answer: d. increase

Explanation:

If the sun were more massive, the gravitational force between the sun and Earth would increase. This means that Earth's gravity with the sun would also increase. Therefore, the correct answer is (D) increase.

The gravitational force between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. So, if the mass of one of the objects increases, the gravitational force between them will also increase. In this case, if the mass of the sun were to increase, the gravitational force between the sun and Earth would become stronger, and hence, Earth's gravity with the sun would also increase.

Both the object's speed and mass affect how much kinetic energy it contains. Motional energy is produced while the roller coaster descends. The roller coaster's bottom of the track position is where the most kinetic energy is produced. Kinetic energy changes to potential energy when it starts to rise.

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The wavelength of the electron is 1.724 × 10^-12 m.

The wavelength of the electron is found  using the de Broglie wavelength formula:

λ = h / p

where λ = wavelength,

h= Planck's constant, a

p =  momentum of the electron.

we find  the momentum of the electron,

p = m * v

p = (9.1 × 10^-31 kg) * (4.2 × 10^7 m/s)

p = 3.822 × 10^-22 kg m/s

Therefore, wavelength ;

λ = h / p

λ = (6.6 × 10^-34 J s) / (3.822 × 10^-22 kg m/s)

λ = 1.724 × 10^-12 m

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The electric force between two point charges is given by the equation

[tex]F=k*q_1*q_2/r^2[/tex]

The interaction between two things is measured by the physical quantity known as force. It is a vector quantity, and the sign F is frequently used to denote it. When an object interacts with another object, it feels a push or a pull.

where r is the distance between the charges, q1 and q2 are their magnitudes, and k is the Coulomb constant.

When we enter the problem's specified values, we obtain

[tex]2.2N=8.99*10^9\ N*m^2/C^2*q*-2q/(1.4 m)^2[/tex]

which simplifies to

q = -0.500 N/C.

Thus, the magnitude of charge q is 0.500 N/C.

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The value of the charge on each particle is [tex]1.05 x 10^-8 C[/tex].

Coulomb's law is a fundamental principle of electrostatics that describes the interaction between electric charges. It states that the force between two point charges is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. We can use Coulomb's law to solve this problem. Mathematically,

[tex]F = k(q1q2)/r^2[/tex]

where F is the force of attraction or repulsion between the two charged particles,[tex]q1[/tex] and [tex]q2[/tex] are the magnitudes of the charges on the two particles, r is the distance between them, and k is Coulomb's constant, which has a value of [tex]9.0 x 10^9 Nm^2/C^2.[/tex]

In this problem, we know that the charges are equal and the distance between them is 10.0 cm. We also know that the force between them is 0.5 N. Therefore,

[tex]0.5 N = k(q^2)/(0.1 m)^2[/tex]

Solving for q, we get:

[tex]q = \sqrt{[(0.5 N)(0.1 m)^2/k]}[/tex]

[tex]q = \sqrt{(0.5 N)(0.01 m)/(9.0 x 10^9 Nm^2/C^2)}[/tex]

[tex]q = 1.05 x 10^-8 C[/tex]

Therefore, the value of the charge on each particle is [tex]1.05 x 10^-8 C.[/tex]

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The original temperature of the mercury is 260.6K

To solve this problem, we can use the formula for the heat released during the solidification of a substance:

Q = m * Lf

where Q is the heat released, m is the mass of the substance, and Lf is the heat of fusion of the substance.

In this case, Q = 157 kJ, m = 5.00 kg, and Lf = 11.3 kJ/kg.

We also need to use the formula for the heat absorbed or released during a temperature change:

Q = m * c * ΔT

where Q is the heat absorbed or released, m is the mass of the substance, c is the specific heat of the substance, and ΔT is the change in temperature.

We can use this formula to calculate the heat released as the mercury cools from its original temperature to its melting point, and then use the formula for solidification to calculate the heat released as the mercury solidifies.

Let T be the original temperature of the mercury.

The heat released as the mercury cools from its original temperature to its melting point is:

Q1 = m * c * (T - 234)

The heat released as the mercury solidifies is:

Q2 = m * Lf

The total heat released is:

Q = Q1 + Q2 = m * c * (T - 234) + m * Lf

Substituting the values given in the problem, we get:

157 kJ = 5.00 kg * 140 J/kg . K * (T - 234) + 5.00 kg * 11.3 kJ/kg

Simplifying and solving for T, we get:

T = 260.6 K

Therefore, the original temperature of the mercury was 260.6 K.

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Answer:

Explanation:

Because you have velocity along the y axis and time along the x axis, this is a velocity v time graph which is an acceleration graph. The slope of the line in this graph IS the acceleration. We can use 2 points and the slope formula to solve for the acceleration:

(0, 0) and (1, 3):

[tex]m=\frac{3-0}{1-0}=3[/tex] m/s squared, choice D.

Mice that ate sunflower seeds gained an average of 2.1 grams that Raphael can determine from his experiment. Each group is given a different type of feed.

Grams (g) is a unit of measurement for mass in the International System of Units (SI). It is the base unit of mass in the SI, and is defined as being equal to the mass of a physical prototype, which is kept at the International Bureau of Weights and Measures. In practical terms, 1 gram is equal to 0.0352739619 ounces, or 0.00220462262 pounds. Grams are often used to measure the weight of food, medicines, and other small objects.

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Answer:

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To solve this problem, we can use the formula for heat transfer:

q = mcΔT

where q is the heat transferred, m is the mass of the object, c is its specific heat capacity, and ΔT is the change in temperature.

We know that the mass of the block is 0.35 kg and that its initial temperature is -27.5 ºC. We also know that the mass of water is 0.217 kg and that its initial temperature is 25.0 ºC.

When they come to equilibrium at 16.4 ºC, we can calculate how much heat was transferred from the water to the block:

q = mcΔT q = (0.217 kg)(4186 J/kg ºC)(25.0 ºC - 16.4 ºC) q = 1825 J

This amount of heat was transferred from the water to the block, so we can set it equal to the amount of heat absorbed by the block:

q = mcΔT 1825 J = (0.35 kg)c(16.4 ºC - (-27.5 ºC)) 1825 J = (0.35 kg)c(43.9 ºC) c = 148 J/kg ºC

Therefore, the specific heat capacity of the block is 148 J/kg ºC.

Explanation:

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The light ray will deviate from its original path with 19.5° after refraction.

Applying Snell's law to calculate the angle of refraction:

n1 sin θ1 = n2 sin θ2

where n1 and θ1 =  the refractive index and the angle of incidence in the first medium (air),

n2 and θ2 =  the refractive index and the angle of refraction in the second medium (glass).

In this example,

n1 = 1.00 (refractive index of air), θ1 = 30°, and

n2 = 1.5 (refractive index of glass).

We then calculate for  θ2:

n1 sin θ1 = n2 sin θ2

1.00 * sin 30° = 1.5 * sin θ2

0.5 = 1.5 * sin θ2

sin θ2 = 0.5 / 1.5 = 1/3

θ2 = sin^-1(1/3)

θ2 = 19.5°

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Aproximately 1.09 m/s was the locust's first speed.

In engineering mechanics, vectors are used to express values with both a magnitude and a direction. For analysis, vector representations of a variety of engineering quantities—including forces, displacements, velocities, and accelerations—are required.

Δy = vsin(θ)t - 0.5gt²

0 = v*sin(55°)t - 0.5(-9.81 m/s²)*t²

t = 2vsin(55°)/g

Now, we can use the horizontal motion of the locust to find the initial velocity v. The horizontal distance traveled by the locust is given by:

Δx = v*cos(55°)*t

Substituting the expression for t that we just found:

0.750 m = vcos(55°)2vsin(55°)/g

Solving for v:

v = √(0.750 mg/(2sin(55°)*cos(55°)))

v ≈ 1.09 m/s

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Answer:

B. Atomic number minus mass number

Explanation:

A cesium-133 atom's radiation goes through 1.5 million cycles in around 0.1633 microseconds (or 163.3 nanoseconds).

9,192,631,770 hertz (cycles per second) is the frequency of the microwave spectral line that the isotope cesium-133 emits. The basic unit of time is provided by this. Cesium clocks have an accuracy and stability of 1 second in 1.4 million years.

The radiation emitted by cesium-133 has a frequency of 9,192,631,770 cycles per second, or 9.192631770 109 Hz.

The following formula may be used to determine how long 1.5 million radiation cycles take to complete:

Time is equal to the frequency of cycles.

Plugging in the numbers, we get:

time = 1.5 million / 9.192631770 × 10^9 Hz

time = 1.632995101 × 10^-7 seconds

So it takes approximately 0.1633 microseconds (or 163.3 nanoseconds) for radiation from a cesium-133 atom to complete 1.5 million cycles.

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The final temperature after adding the ice to the water and calorimeter will be approximately 8.37 ◦C.

What is Temperature?

Temperature is a measure of the average kinetic energy of the particles in a substance or system. It is a scalar quantity that indicates how hot or cold an object or medium is. Temperature is commonly measured using various scales, such as Celsius (°C), Fahrenheit (°F), and Kelvin (K), which represent different reference points and units of measurement.

Since energy is conserved, we can set Q_ice equal to Q_water+calorimeter:

m_ice * c_ice * ΔT_ice = (m_water + m_calorimeter) * c_water+calorimeter * ΔT_water+calorimeter

27 g * 2090 J/kg ◦C * (T_f + 65) = (525 g + 80 g) * (4186 J/kg ◦C + 387 J/kg ◦C) * (T_f - 25)

Simplifying and solving for T_f:

27 * 2090 * (T_f + 65) = 605 * (T_f - 25)

56130 T_f + 361350 = 605 T_f - 15125

56130 T_f - 605 T_f = -15125 - 361350

-44,970 T_f = -376475

T_f = (-376475) / (-44,970)

T_f ≈ 8.37 ◦C

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Answer:

A) P.E = 138.44 J

B) The velocity of swing at bottom, v = 3.33 m/s

C) The work done, W = -138.44 J

Explanation:

Given,

The mass of the child, m = 25 Kg

The length of the swing rope, L = 2.2 m

The angle of the swing to the vertical position, ∅ = 42°

A) The potential energy at the initial position ∅ = 42° is given by the relation

                               P.E = mgh joule

Considering h  = 0 for the vertical position

The h at ∅ = 42° is  h = L (1 - cos∅)

                              P.E = mgL (1 - cos∅)

Substituting the given values in the above equation

                              P.E = 25 x 9.8 x 2.2 (1 - cos42°)

                                     = 138.44 J

The potential energy for the child just as she is released, compared to the potential energy at the bottom of the swing is, P.E = 138.44 J

B) The velocity of the swing at the bottom.

At bottom of the swing the P.E is completely transformed into the K.E

                 ∴                 K.E = P.E

                                    1/2 mv² = 138.44

                                    1/2 x 25 x v² 138.44

                                           v² = 11.0752

                                            v = 3.33 m/s

The velocity of the swing at the bottom is, v = 3.33 m/s

C) The work done by the tension in the rope from initial position to the bottom

            Tension on string, T = Force acting on the swing, F

                           =

                           = - 2.2 x 25 x 9.8 [cos0 - cos 42°]

                           = - 138.44 J

The negative sign in the in energy is that the work done is towards the gravitational force of attraction.

The work done by the tension in the ropes as the child swings from the initial position to the bottom of the swing, W = - 138.44 J

The system's final temperature is roughly 16.7°C.

You may determine your substance's final heat by multiplying the temperature change by the initial temperature. Your water's final temperature would be 24 + 6, or 30 degrees Celsius, for instance, if it started off at 24 degrees Celsius.

The following is the formula for energy conservation:

Q1 + Q2 = 0

Q = mcΔT

Q1 + Q2 = 0

568.8

Simplifying and solving for

6394.4 - 106768 = 0

= 16.7°C

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The force needed to lift the 1800 kg car with the small piston is 2,649 N or approximately 270 kg (since 1 kg is equal to 9.81 N).  

The hydraulic lift works based on Pascal's principle, which states that the pressure applied to a confined fluid is transmitted equally in all directions throughout the fluid.

Assuming there is no loss of energy due to friction or other factors, the force exerted on the small piston will be equal to the force exerted on the large piston. This can be expressed as:

F1/A1 = F2/A2

where F1 is the force exerted on the large piston, A1 is the area of the large piston, F2 is the force exerted on the small piston (which we want to find), and A2 is the area of the small piston.

We can rearrange this equation to solve for F2:

F2 = (F1/A1) x A2

Given that the area of the large piston is 100 cm², we can calculate the force exerted on the large piston by using the weight of the car and the gravitational acceleration:

F1 = m x g = 1800 kg x 9.81 m/s² = 17,658 N

Substituting the values into the equation, we get:

F2 = (17,658 N / 100 cm2) x 15 cm² = 2,649 N

Therefore, the force needed to lift the 1800 kg car with the small piston is 2,649 N or approximately 270 kg (since 1 kg is equal to 9.81 N).

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Two or greater sources are said to be coherent if they emit waves that have the identical wavelength (or frequency) and amplitude and which maintain a steady phase difference.

If two sources have the identical wavelength, frequency, and segment difference, they are said to be coherent. Therefore, we can conclude that coherent sources have the identical wavelength.

Two microwave coherent factor sources emitting waves of wavelenths λare positioned at 5λdistance apart. The interference is being observed on a flat non-reflecting surface alongside a line passing through on sources ,in a course perpendicular to the line joining the two sources

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A sound that is 7.8x10-4 W/m2 in intensity is equal to (10 dB)log3.2106 W/m21012 W/m2=185 dB.

The decibel, often known as the db or 0.1 bel, is the standard measurement unit. Hence, b = 10 log10 (I/I0) can be used to express the relationship between relative intensities, or b, in decibels. This equation can be used to determine that one decibel equals a 26 percent intensity variations.

The "decibel level" of a sound is a less formal term for relative intensity level. It is not the same as energy; relative intensity level reflects loudness more faithfully by using a logarithmic scale.

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The Universe became dominated by matter instead of radiation at a redshift of around 3300.

To determine at what redshift the Universe became dominated by matter, we need to find the redshift at which the energy density of matter becomes equal to the energy density of radiation.

Let's start with the energy density of radiation, which can be calculated using the Stefan-Boltzmann law:

$[tex]u_{rad} = \frac{4\sigma}{c}T^4$[/tex]

where $\sigma$ is the Stefan-Boltzmann constant, $c$ is the speed of light, and $T$ is the temperature of the radiation. Since we are assuming that the cosmic microwave radiation is a black-body radiation, we can use the temperature of 2.73 K, which corresponds to the peak of the radiation curve:

[tex]$u_{rad} = \frac{4\sigma}{c}(2.73K)^4 \approx 0.261 \text{ eV/cm}^3$[/tex]

Next, let's calculate the energy density of matter. We know that the number density of baryons is [tex]$n_b \approx \frac{1}{10^9}n_{\gamma}$, where $n_{\gamma}$[/tex] is the number density of photons. Since we are assuming that the photon-to-baryon ratio is constant, we can write:

[tex]$\frac{\rho_b}{\rho_{\gamma}} = \frac{m_b n_b}{\frac{4}{3}\sigma T^4} = \frac{3m_b}{4\sigma T^3 n_{\gamma}} \approx \frac{3m_b}{4\sigma T^3}\frac{1}{n_{\gamma}}$[/tex]

where $m_b$ is the mass of a baryon. Substituting the values, we get:

[tex]$\frac{\rho_b}{\rho_{\gamma}} \approx 4.15 \times 10^{-10}$[/tex]

Since the total energy density of the Universe is given by:

[tex]$\rho_{tot} = \rho_b + \rho_{\gamma}$[/tex]

we can write:

[tex]$\frac{\rho_b}{\rho_{tot}} = \frac{\rho_b}{\rho_b + \rho_{\gamma}} \approx \frac{\rho_b}{\rho_{\gamma}} = 4.15 \times 10^{-10}$[/tex]

At the redshift $z$, the energy density of radiation will be diluted by a factor of $[tex](1+z)^4[/tex]$, while the energy density of matter will be diluted by a factor of $[tex](1+z)^3[/tex]$. Thus, at some redshift $z$, we will have:

$  [tex]\frac{\rho_b}{\rho_{tot}} = \frac{\rho_b}{\rho_b + \rho_{\gamma}} = \frac{1}{1+z}\frac{3m_b}{4\sigma T^3 n_{\gamma}}[/tex]   $

Setting this equal to the value we calculated above, we can solve for $z$:

$   [tex]\frac{1}{1+z}\frac{3m_b}{4\sigma T^3 n_{\gamma}} \approx 4.15 \times 10^{-10}[/tex]  $

$  [tex]1+z \approx \frac{3m_b}{4\sigma T^3 n_{\gamma}}\frac{1}{4.15 \times 10^{-10}}[/tex]  $

$ [tex]z \approx 3300[/tex] $

Therefore, the Universe became dominated by matter instead of radiation at a redshift of around 3300.

To know more about density:

https://brainly.com/question/29775886

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