PLEASE PLEADE HELP!?!?

The universe could be considered an isolated system because (2 points) Select one:
a. many people think that no energy or matter exists outside the universe.

b. energy and matter are created in the universe and flow freely into and out of the universe.

c. energy is created outside the universe and matter is created within the universe.

d. energy is created in the universe and matter is transferred out of the universe.

Answers

Answer 1
A. since the universe has no matter or energy on the outside
Answer 2

Answer: a. many people think that no energy or matter exists outside the universe.

Explanation: The universe isolated because everything is within it and nothing is on the outside. There is no exchange of energy or matter between the universe and its surroundings. Thus since it is isolated, there can be no exchange of energy with anything.


Related Questions

When violet light of wavelength 415 nm falls on a single slit, it creates a central diffraction peak that is 9.90 cm wide on a screen that is 2.53 m away. how wide is the slit?

Answers

Final answer:

The width of the slit when violet light of 415 nm wavelength creates a central diffraction peak of 9.90 cm on a screen 2.53 m away is approximately 10.6 μm.

Explanation:

The wavelength of violet light is given as 415 nm, and it produces a diffraction pattern with a central peak width of 9.90 cm on a screen 2.53 meters away. We can find the width of the slit using the formula for single-slit diffraction:

Δy = λL/a

where Δy is the width of the central peak, λ is the wavelength, L is the distance to the screen, and a is the width of the slit. Rearranging the formula to solve for a, we have:

a = λL/Δy

Substituting the provided values:

a = (415 x 10^-9 m)(2.53 m) / (9.90 x 10^-2 m)

After calculating, we find that the width of the slit (a) is approximately:

a ≈ 1.06 x 10^-5 m or 10.6 μm

Using the single-slit diffraction formula and given values, we calculate the width of the slit to be 21.1 μm.

To solve this problem, we'll use the formula for the width of the central peak in a single-slit diffraction pattern:

w = 2Lλ / a

Where:

w = width of the central peak (9.90 cm = 0.099 m)L = distance from the slit to the screen (2.53 m)λ = wavelength of violet light (415 nm = 415 x 10⁻⁹ m)a = width of the slit (what we need to find)

Rearranging the formula to solve for a:

a = 2Lλ / w

Substituting the given values:

a = (2 * 2.53 m * 415 x 10⁻⁹ m) / 0.099 m

Now, calculate:

a = 2.11 x 10⁻⁵ m or 21.1 μm

Therefore, the width of the slit is 21.1 μm.

A camera with a 50.0-mm focal length lens is being used to photograph a person standing 3.00 m away. if the film is 36.0 mm high, what fraction of a 1.75-m-tall person will fit on it?

Answers

f = 50.0mm = 5.0cm
d₀ = 3.00m = 3.00cm
1/f = 1/d₀ + 1/di
= 1/di = 1/5 - 1/325 = 5.078 cm
m= hi/h₀ = di/d₀ = 5.078/300
hi/h₀ = 169.29
hi = 1692.9 cm

The absolute (or total) pressure at the bottom of a cylindrical container with a cross-sectional area of 47.0 cm2 and holding a fluid of density 560 kg/m3 is 115 kpa. (a) determine the depth of the fluid.

Answers

Final answer:

The fluid's depth in the cylinder can be determined using the equation for fluid pressure, h = P / (pg), and plugging in given values, resulting in an approximated depth of 20.9 meters.

Explanation:

The total absolute pressure at a point in a fluid is the sum of the atmospheric pressure and the pressure due to the fluid above the point of reference. The latter is given by the equation P = pgh, where p is the density of the fluid, g is the acceleration due to gravity and h is the height (or depth) of the fluid column above the point of reference. In this scenario, we know P (absolute pressure, 115 kPa), p (density, 560 kg/m3), and g (standard gravity, roughly 9.81 m/s2), and we want to find h.

To find h, we can rearrange our equation: h = P / (pxg) . Plugging the given values we have h=115000Pa/(560kg/m3*9.8m/s2), which gives h = 20.9 m.

This means the depth of the fluid in the cylinder is approximately 20.9 meters.

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1) A substance has a half life of 20 years. what percentage would be left after 40 years?

2)After 4 half lifes of uranium, 10 grams of the uranium remains. how much uranium did you start with?

Answers

1) The half-life is the time required for a substance to reduce to half its initial value. In formulas:
[tex] \frac{m(t)}{m_0} = ( \frac{1}{2} )^{t/t_{1/2}}[/tex] (1)
where
m(t) is the amount of substance left at time t
m0 is the initial mass
[tex]t_{1/2}[/tex] is the half-life

In this problem, the half-life of the substance is 20 years:
[tex]t_{1/2} = 20 y[/tex]
therefore, the fraction of sample left after t=40 years will be
[tex] \frac{m(t)}{m_0}=( \frac{1}{2})^ \frac{40 y}{20 y} = ( \frac{1}{2})^2 = \frac{1}{4} [/tex]

So, only 1/4 of the original sample will be left, which corresponds to 25%.

2) We can use again formula (1), by re-arranging it:
[tex]m_0 = \frac{m(t)} {( \frac{1}{2} )^{ \frac{t}{t_{1/2} }}}[/tex]
If we use m(t)=10 g (mass of uranium left at time t), and [tex]t=4 t_{1/2}[/tex] (the time is equal to 4 half lifes), we get
[tex]m_0 = \frac{10 g}{ (\frac{1}{2})^4 } =16 \cdot 10 g = 160 g[/tex]
So, the initial sample of uranium was 160 g.

Two moles of an ideal gas are compressed in a cylinder at a constant temperature of 80.0 ∘c until the original pressure has tripled. calculate the amount of work done by gas.

Answers

The work done by a gas during an isothermal process is given by:
[tex]W=nRT ln \frac{V_f}{V_i} [/tex] (1)
where
n is the number of moles of the gas
R is the gas constant
T is the absolute temperature of the gas
[tex] \frac{V_f}{V_i} [/tex] is the ratio between the final volume and the initial volume of the gas

We need to calculate this ratio, and we can do it by using the gas pressure. In fact, for an isothermal process, Boyle's law states that the product between pressure and volume of the gas is constant:
[tex] pV=k [/tex]
which can be rewritten as
[tex] p_i V_i= p_f V_f[/tex]
which is equivalent to
[tex] \frac{V_f}{V_i}= \frac{p_i}{p_f} [/tex]
The problem says that the pressure of the gas is tripled, therefore the ratio between final and initial volume is:
[tex] \frac{V_f}{V_i} = \frac{p_i}{3 p_i} = \frac{1}{3} [/tex]

Now we can use eq.(1) to calculate the work done by the gas. The absolute temperature is
[tex]T=80.0^{\circ}C+273 = 353 K[/tex]
The number of moles is n=2, therefore the work done is
[tex]W=nRT ln \frac{V_f}{V_i}=(2 mol)(8.31 J/mol K) (353 K) \ln \frac{1}{3}= -6445 J[/tex]
And the work is negative, because it is done by the environment on the gas (the gas is compressed)

Final answer:

The work done by two moles of an ideal gas compressed isothermally in a cylinder can be calculated using the formula W = nRT ln(V1/V2). The work is generally negative as the gas does work on its surroundings during the process.

Explanation:

When an ideal gas is compressed in a cylinder, the work done by the gas can be calculated using the principles of thermodynamics. Specifically, if the gas is compressed isothermally (at a constant temperature), the work done by the gas during this process can be calculated using the formula W = nRT ln(V1/V2), where n represents the number of moles of gas, R is the universal gas constant, T is the temperature in Kelvin, and V1 and V2 are the initial and final volumes of the gas respectively.

In the scenario presented, we have 2 moles of gas, a temperature of 80.0°C, and the original pressure being tripled during the compression. This tripling of pressure corresponds to reduction in volume to one third. From these values, we can calculate the work done by the gas during compression. However, we do not have specific information about the volumes or pressures, so we cannot calculate a numerical value. In general, though, we can say the work done by the gas during an isothermal process is negative, as it is compressed and does work on its surroundings.

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Make a rule: how would you find the resistance of a parallel circuit with n identical resistors?

Answers

When n resistors are connected in parallel, it means they are connected to the same potential difference V:
[tex]V=V_1 =V_2 =...=V_n[/tex] (2)
It also means that the total current in the circuit is given by the sum of the currents flowing through each branch (each resistor) of the circuit:
[tex]I=I_1+I_2 +...+I_n[/tex] (1)

By using Ohm's law:
[tex]I= \frac{V}{R} [/tex]
we can rewrite (1) as
[tex] \frac{V}{R_{eq}} = \frac{V_1}{R_1}+ \frac{V_2}{R_2}+...+ \frac{V_n}{R_n} [/tex]
However, we said that the potential difference across each resistor is equal (eq.(2)), so we can rewrite the last formula as
[tex] \frac{V}{R_{eq}} = \frac{V}{R_1}+ \frac{V}{R_2}+...+ \frac{V}{R_n}[/tex]
From which we find an expression for the equivalent resistance of n resistors in parallel:
[tex] \frac{1}{R_{eq}}= \frac{1}{R_1}+ \frac{1}{R_2}+....+ \frac{1}{R_n} [/tex]
Final answer:

To find the resistance of a parallel circuit with n identical resistors, divide the resistance of one resistor by n.

Explanation:

The rule to find the resistance of a parallel circuit with n identical resistors is to divide the value of one resistor by the number of resistors (n). So, the formula is Requiv = R/n, where R is the resistance of one resistor and n is the number of resistors in parallel.

When you have n identical resistors in parallel, you can find the equivalent resistance (Requiv) using the formula:

Requiv = R / n

Where:

Requiv is the equivalent resistance of the parallel combination.

R is the resistance of one individual resistor.

n is the number of identical resistors in parallel.

This formula simplifies the calculation and is useful when you want to determine the overall resistance in a parallel circuit, which is a common scenario in electrical circuits and electronics.

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A diver 40 m deep in 10∘C fresh water exhales a 1.0-cm-diameter bubble.

What is the bubble's diameter just as it reaches the surface of the lake, where the water temperature is 20∘C? Assume that the air bubble is always in thermal equilibrium with the surrounding water.
Express your answer to two significant figures and include the appropriate units.

Answers

The diameter of the air bubble when it reaches the surface is about 1.7 cm

[tex]\texttt{ }[/tex]

Further explanation

The basic formula of pressure that needs to be recalled is:

Pressure = Force / Cross-sectional Area

or symbolized:

[tex]\large {\boxed {P = F \div A} }[/tex]

P = Pressure (Pa)

F = Force (N)

A = Cross-sectional Area (m²)

Let us now tackle the problem !

[tex]\texttt{ }[/tex]

In this problem , we will use Ideal Gas Law as follows:

Given:

initial diameter of bubble = d₁ = 1.0 cm

initial depth of the diver = h = 40 m

initial temperature = T₁ = 10 + 273 = 283 K

atmospheric pressure = Po = 1.0 atm = 10⁵ Pa

final temperature = T₂ = 20 + 273 = 293 K

density of water = ρ = 1000 kg/m³

Unknown:

final diameter of bubble = d₂ = ?

Solution:

[tex]\frac{P_1V_1}{T_1} = \frac{P_2V_2}{T_2}[/tex]

[tex]\frac{P_1 (\frac{1}{6} \pi (d_1)^3)}{T_1} = \frac{P_2(\frac{1}{6} \pi (d_2)^3)}{T_2}[/tex]

[tex]\frac{P_1 (d_1)^3}{T_1} = \frac{P_2 (d_2)^3}{T_2}[/tex]

[tex]\frac{(P_o + \rho g h ) (d_1)^3}{T_1} = \frac{P_o (d_2)^3}{T_2}[/tex]

[tex]\frac{(10^5 + 1000(9.8)(40) ) (1.0)^3}{283} = \frac{10^5(d_2)^3}{293}[/tex]

[tex]\frac{(492000 ) (1.0)^3}{283} = \frac{10^5(d_2)^3}{293}[/tex]

[tex]d_2 \approx 1.7 \texttt{ cm}[/tex]

[tex]\texttt{ }[/tex]

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[tex]\texttt{ }[/tex]

Answer details

Grade: High School

Subject: Physics

Chapter: Pressure

By applying the ideal gas law, we find the diameter at the surface to be approximately 1.7 cm.

To determine the bubble's diameter when it reaches the surface, we use the ideal gas law. Since temperature and volume are directly proportional under constant pressure, we can express this relationship as:

(V₁/T₁) = (V₂/T₂)

where,

V₁ = initial volume of the bubble   T₁ = initial temperature of the water (10°C = 283 K)V₂ = final volume of the bubbleT₂ = final temperature of the water (20°C = 293 K)

Given that V₁ is π(0.005 m)² * h (since the volume of a sphere is directly proportional to the radius cubed), we know the final volume V₂ will change due to both temperature and the reduction in pressure as the bubble rises.

Hydrostatic pressure P₁ at 40 meters depth is given by:

P₁ = P₀ + ρgh

P₀ = atmospheric pressure = 1 atmρ = density of water ≈ 1000 kg/m³g = 9.8 m/s²h = 40 m

P₁ ≈ 1 + (1000 * 9.8 * 40) / 101325 ≈ 4.93 atm

At the surface, the only pressure is P₀ (1 atm).

Using the combined gas law P₁V₁/T₁ = P₂V₂/T₂:

4.93V₁/283 = 1V₂/293

Solving for V₂ we get:

V₂ = 4.93 * V₁ * 293 / 283

V₂ ≈ 5.09 * V₁

Since the volume ratio (D₂/D₁)³ = 5.09, taking the cube root:

D₂ ≈ 1.71 * D₁

So, if initial diameter D₁ is 1.0 cm:

D₂ = 1.71 * 1.0 cm ≈ 1.7 cm

Therefore, the bubble's diameter at the surface is approximately 1.7 cm.

Which choice shows the size range for nanotechnology?

Answers

Answer:

C

Explanation:

10–9 m to 10–7 m

The size range for nanotechnology is 10⁻⁹ m to 10⁻⁷ m.

What is nanotechnology?

Nanotechnology improves and revolutionize, The new technology used in industry sectors like information technology, homeland security, medicine, transportation, energy, food safety, and environmental science.

A material with its dimensions less than 100 nanometers or ranging between 1 to 100nm are known as nanomaterials.

Thus, the correct choice is C.

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A light source emits a beam of photons, each of which has a momentum of 2.7 × 10-29 kg·m/s. (a) what is the frequency of the photons? (b) to what region of the electromagnetic spectrum do the photons belong?

Answers

The frequency of the photons is equal to 1.22 ×10¹³ Hz and lies in the infrared region of the electromagnetic spectrum.

What is the frequency?

The frequency of the photons or light can be described as the number of oscillations in one second. The frequency possesses S.I. units per second or Hertz.

The relationship between momentum (p), frequency (ν), and speed of light (c) is:

p = hν/c

ν = pc/h

Given, the momentum of the photons, p = 2.7 ×10⁻²⁹ Kg.m/s

The speed of light, c = 3×10⁸ m/s

The plank's constant, h = 6.626 ×10⁻³⁴ Js

The frequency of the photons can determine from the above-mentioned relationship:

ν = (2.7 × 10⁻²⁹).( 3 × 10⁸)/ 6.626 × 10⁻³⁴

ν = 1.22 × 10¹³ Hz

Therefore, the frequency of the photons is 1.22 × 10¹³ Hz and lies in the infrared region of the spectrum.

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Calculate the magnitude of the angular momentum of the earth in a circular orbit around the sun. mastering

Answers

The angular momentum of the Earth around the Sun is given by:
[tex]L=m \omega r^2[/tex]
where 
m is the Earth's mass
[tex]\omega[/tex] is the Earth's angular velocity
r is the average distance of the Earth from the Sun

The Earth takes 365 days to make a complete revolution around the Sun, which corresponds to
[tex]t=365 d \cdot 24 \cdot 60 \cdot 60 =3.15 \cdot 10^7 s[/tex]
A complete revolution corresponds to [tex]2 \pi rad[/tex], therefore the Earth's angular velocity is
[tex]\omega = \frac{2 \pi rad}{3.15 \cdot 10^7 s}=1.99 \cdot 10^{-7} rad/s [/tex]

The average distance of Earth from the Sun is 149.6 million km:
[tex]r=149.6 Mkm = 149.6 \cdot 10^9 m[/tex]

And the Earth's mass is [tex]m=5.97 \cdot 10^{24} kg[/tex], therefore its angular momentum is
[tex]L=m \omega r^2 =(5.97 \cdot 10^{24} kg)(1.99 \cdot 10^{-7} rad/s)(149.6 \cdot 10^9 m)^2=[/tex]
[tex]=2.66 \cdot 10^{40} kg m^2/s[/tex]

What is the maximum power consumption of a 3.0-v portable cd player that draws a maximum of 330 ma of current?

Answers

The power used by an electrical device is given by:
[tex]P=VI[/tex]
where V is the potential difference through the device while I is the current flowing through it.

For the cd-player in our problem, [tex]V=3.0 V[/tex], while the current is
[tex]I=330 mA=0.33 A[/tex]
Therefore, the power used is
[tex]P=VI=(3.0 V)(0.33 A)=0.99 W[/tex]

Final answer:

The maximum power consumption of a 3.0-v portable CD player drawing 330 mA of current is calculated using the formula P = IV, giving a result of 0.99 W, which is not directly listed in the provided options.

Explanation:

The question asks for the maximum power consumption of a 3.0-volt portable CD player that draws a maximum of 330 milliamps of current. To find the power, we use the formula P = IV, where P is the power in watts, I is the current in amperes, and V is the voltage in volts.

In this case, I = 330 mA = 0.33 A (since 1A = 1000mA), and V = 3.0 V. Substituting these values into the formula gives:

P = 0.33 A × 3.0 V = 0.99 W.

A crying baby emits sound with an intensity of 8.0 × 10-8 w/m2. calculate a reasonable estimate for the intensity level from a set of quintuplets (five babies), all crying simultaneously at the same place? the lowest detectable intensity is 1.0 × 10-12 w/m2.

Answers

Sound intensity of 1 baby, I = 8*10^-8 W/m^2

The sound heard should be higher by:

10*log (n) where for 5 babies, n = 5. Then
10*log (n) = 10*log (5) ≈ 7 dB

Also give is the reference sound, Io = 1.0*10^-12 W/m^2

Therefore,
Sound intensity, L1 = 10*log (I/I1) = 10*log [(8*10^-8)/(1*10^-12)] ≈ 49 dB
Therefore, total intensity for the five babies is:

Total intensity = 49+7 = 56 dB

The intensity level from a set of quintuplets (five babies) : 56 dB

Further explanation

Wave intensity is the power of a wave that is moved through a plane of one unit that is perpendicular to the direction of the wave

Can be formulated

[tex]\rm I=\dfrac{P}{A}[/tex]

I = intensity, W m⁻²

P = power, watt

A = area, m²

The farther the distance from the sound source, the smaller the intensity

[tex]\rm \dfrac{I_2}{I_1}=\dfrac{(r_1)^2}{(r_2)^2}[/tex]

So the intensity is inversely proportional to the square of the distance from the source

[tex]\rm I\approx \dfrac{1}{r^2}[/tex]

Intensity level (LI) can be formulated

[tex]\rm LI=10\:log\dfrac{I}{I_o}[/tex]

Io = 10⁻¹²

For the level of intensity of several sound sources as many as n pieces can be formulated:

LIn = LI1 + 10 log n

The intensity level of 1 baby is

[tex]\rm LI=10\:log\dfrac{8.10^{-8}}{10^{-12}}[/tex]

LI = 10 log 8.10⁴

LI = 49

The intensity level of 5 babies :

LI5 = LI + 10 log n

LI5 = 49 + 10 log 5

LI5 = 49 + 7

LI5 = 56

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The pressure exerted by a phonograph needle on a record is surprisingly large. if the equivalent of 1.00 g is supported by a needle, the tip of which is a circle 0.210 mm in radius, what pressure is exerted on the record in n/m2?

Answers

Pressure, P = Force, F/ Surface Area, A

In the current scenario,
Force, F = Weight = mg = 1/1000*9.81 = 9.81*10^-3 N
Surface area, A = πr^2 = π*(0.210/1000)^2 = 1.385*10^-7 m^2

Therefore,
P = F/A = (9.81*10^-3)/(1.385*10^-7) = 70,807.71 N/m^2
Final answer:

The pressure exerted by a phonograph needle on a record, if the equivalent of 1g is supported by the needle with a radius of 0.210 mm, is approximately 7.05*10^7 Pa or N/m².

Explanation:

The pressure exerted by a phonograph needle on a record is calculated using the formula for pressure: P = F / A . To obtain the force (F), we multiply the mass of the needle (1g or 0.001 kg) by the acceleration due to gravity (9.8 m/s²). This yields a force of 0.0098 N. The area (A) is calculated using the formula for the area of a circle, A=πr², where r is the radius of the needle tip (0.210 mm or 0.00021 m). So, the area amounts to roughly 0.000000139 m². The resulting pressure (P), when calculated comes out to be approximately 7.05*10^7 Pa or N/m².

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Which of the following is not a fossil fuel?
a.
oil
c.
coal
b.
natural gas
d.
hydrogen

Answers

Hello,

Hydrogen is NOT a fossil fuel that has been listed so the correct choice would be "d". Oil, coal, and natural gas are all fossil fuels which come from the remains of animals and plants from nearly 300 million years ago. 

Let me know if you need anything else.

                   - Dotz :)
The answer is d hydrogen

Explain why wet clothes that are hung on a washing line dry best

Answers

because the sun evaporates the water out of the clothes

a brick is suspended above the ground at a height of 6.6 m. it has a mass of 5.3 kg. what is the potential energy of the brick

Answers

The formula for potential energy is
E(p) = mgh

(Mass x gravity x height)

Therefore energy = (5.3)(9.8)(6.6)
= 342.8 J

How did I get 9.8?
9.8 is the constant for gravity

Nickel is a common ferromagnetic material. t/f

Answers

This is true. Nickel is one of the elements present on a rather short list of ferromagnetic materials, along with iron, cobalt, and neodymium, amongst others.

A 10 µf capacitor is charged to 108 v and is then connected across a 328 ω resistor. what is the initial charge on the capacitor? answer in units of µc.

Answers

The capacitance is defined as the maximum charge stored in a capacitor, Q, divided by the voltage applied, V:
[tex]C= \frac{Q}{V} [/tex]

The capacitor is initially charged with the battery of 108 V, so the the initial charge on the capacitor can be found by re-arranging the previous formula:
[tex]Q=CV=(10 \mu F)(108 V)=1080 \mu C[/tex]

What is the frequency of a photon that has the same momentum as a neutron moving with a speed of 1.90 × 103 m/s?

Answers

The frequency of a photon can be determined by relating its momentum to the speed of a neutron. The resulting frequency is 4.8 × 10¹4 Hz.

The frequency of a photon can be calculated using the relation between momentum and speed. Given that the speed of a neutron is 1.90 × 103 m/s, the frequency of the photon with the same momentum would be 4.8 × 10¹4 Hz.

help asap please!! An aluminum block of mass 12.00 kg is heated from 20 C to 118 C. If the specific heat of aluminum is 913 J-1 kg K-1 then how much energy is required?
A. 10.956 kJ
B. 1073.688 kJ
C. 64.640 kJ
D. 7456.167 kJ

Answers

Q = mCΔT, where Q = Amount of energy required, m = mass of the blcok, C = specific heat, ΔT = change in temperature.

Using the given values;

Q = 12*913*(118-20) = 1073688 J = 1073.688 kJ.

The correct answer in B.

A steam turbine operates at a boiler temperature of 450 k and an exhaust temperature of 300 k. what is the maximum theoretical efficiency of this system?

Answers

The maximum theoretical efficiency of the system is the one corresponding to the efficiency of a Carnot cycle operating between the same temperatures of the system:
[tex]\eta=1- \frac{T_c}{T_h} [/tex]
where [tex]T_c[/tex] and [tex]T_h[/tex] are the cold and hot temperatures, respectively.
In our problem, [tex]T_c=300 K[/tex] and [tex]T_h=450 K[/tex], therefore the maximum theoretical efficiency is
[tex]\eta=1- \frac{300 K}{450 K}=0.33 [/tex]
So, 33%.
Final answer:

The maximum theoretical efficiency of a steam turbine operating at a boiler temperature of 450 K and an exhaust temperature of 300 K, as calculated by the Carnot efficiency, is approximately 33%.

Explanation:

The efficiency of a heat engine like a steam turbine can be evaluated using the Carnot efficiency formula. The Carnot efficiency formula is 1 - Tc/Th where Tc is the cold reservoir temperature (exhaust temperature) and Th is the hot reservoir temperature (boiler temperature). Given in the problem, Tc=300K and Th=450K:

Efficiency = 1 - Tc/Th

= 1 - 300 K / 450 K = 1 - 0.67 approximately

So, the maximum theoretical efficiency of the steam turbine would be about 33% according to the Carnot efficiency.

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If a hydrogen atom in the ground state absorbs a photon of energy 12.09 ev, to which state will the electron make a transition?

Answers

The energy levels of the hydrogen atom are given by
[tex]E_n = -13.6 \frac{1}{n^2} [eV][/tex] (1)
where n is the level number. Therefore, the ground state has energy of
[tex]E_1 = -13.6 \frac{1}{1^2} eV = -13.6 eV[/tex]

If the atom absorbs a photon of energy [tex]E=12.09 eV[/tex], the final energy of the hydrogen atom is
[tex]E_f = E_1 + E = -13.6 eV + 12.09 eV =-1.51 eV[/tex]

And we can use eq.(1) to find the corresponding level number:
[tex]n= \sqrt{ \frac{-13.6 eV}{E_f} } = \sqrt{ \frac{-13.6 eV}{-1.51 eV}}= \sqrt{9}=3 [/tex]
So, the electron made a transition to the n=3 level.

which change is the best example of a physical change 1) a cookie baking 2) paper burning 3) ice cream melting 4) a nail rusting

Answers

Hey there! :D

We want to find an answer choice that is reversible. If the physical change could have some way of being fixed, then it is a physical change. If it is a chemical change, the make-up is different and there is no way that it could change. 

A cookie baking cannot be reversed. Cookies cannot go back to being cookie dough. 

Paper burning cannot be reversed. Ashes and smoke cannot go back to being paper. 

However, if your ice cream melts, you can refreeze it. Therefore, "3" is the best answer to the question. 

I hope this helps!
~kaikers 


If 3.0 × 10^15 electrons flow through a section of a wire of diameter 2.0 mm in 4.0 s, what is the current in the wire? (e = 1.60 × 10^-19 c)

Answers

Using the given relationship between electrons and coulombs;

1 e = 1.60*10^-19 C

Total charge = 3.0*10^15*1.6*10^-19 = 4.8*10^-4 C

Current = Coulombs/Time = (4.8*10^-4)/4 = 1.2*10^-4 C/s = 1.2*10^-4 Amps

Current in amperes, A = 0.00012 A = 0.12 mA

The current through the wire is of 0.00012 amperes.

How to find the current?

By definition, current will be equal to the quotient between the total charge that flows and the time in which it flows.

Here we have 3.0*10^15 electrons, each one with charge:

e = 1.6*10^(-19) C

Then the total charge that we have is:

Q = (1.6*10^(-19) C)*(3.0*10^15) = 0.00048 C

Finally, the current is:

I = Q/T

where:

Q = 0.00048 CT = 4.0 s

I = (0.00048 C)/(4s) = 0.00012 A

If you want to learn more about current, you can read:

https://brainly.com/question/14010194

Benjamina started her walk from the front door of her ground floor apartment. She walked 6 meters to the corner of the building and then turned the corner and walked 10 meters to her friend’s apartment. Identify the difference between the distance she walked and her displacement.

Answers

The distance is the total distance she walked which is 16 meters adding the 6 meters to the corner and 10 meters to her friend's apartment. Her displacement is the distance from her original starting point so you set up a triangle with side lengths of 6 and 10 and solve for the hypotenuse which gives you a displacement of 11.66 meters.  

Answer:

The change in her position (from beginning to end), along with the direction, is considered her displacement. This value is a measurement and a direction. The total distance along the path from her starting point to her end point is considered her distance. This value is a measurement only.

Explanation:

A ball is thrown vertically upward with a speed of 1.53 m/s from a point 4.21 m above the ground. calculate the time in which the ball will reach the ground.

Answers

The ball moves by uniformly accelerated motion, and its vertical position at time t is described by the following law
[tex]y(t) = h+v_0t - \frac{1}{2}gt^2 [/tex]
where
[tex]h=4.21 m[/tex] is the initial height from which the ball starts its motion
[tex]v_0=1.53 m/s[/tex] is the initial velocity of the ball
[tex]g=9.81 m/s^2[/tex] is the gravitational acceleration

The time in which the ball reaches the ground is the time t at which the vertical position y(t) becomes zero:
[tex]0= h + v_0 t - \frac{1}{2}gt^2[/tex]
Which means
[tex]0=4.21 + 1.53 t - 4.9 t^2 [/tex]

whose solutions are:
[tex]t=-0.78 s[/tex]
[tex]t=1.10 s[/tex]
Neglecting the negative solution (since it has no physical meaning), we can say that the ball reaches the ground after 1.10 s.

The time in which the ball will reach the ground is about 1.10 s

Further explanation

Acceleration is rate of change of velocity.

[tex]\large {\boxed {a = \frac{v - u}{t} } }[/tex]

[tex]\large {\boxed {d = \frac{v + u}{2}~t } }[/tex]

a = acceleration ( m/s² )

v = final velocity ( m/s )

u = initial velocity ( m/s )

t = time taken ( s )

d = distance ( m )

Let us now tackle the problem !

This problem is about Kinematics.

We will solve it in the following way

Given:

initial speed = u = 1.53 m/s

initial height = H = 4.21 m

Unknown:

time taken = t = ?

Solution:

[tex]H = ut - \frac{1}{2}gt^2[/tex]

[tex]-4.21 = 1.53t - \frac{1}{2}(9.8)t^2[/tex]

[tex]-4.21 = 1.53t - 4.9t^2[/tex]

[tex]4.9t^2 - 1.53t - 4.21 = 0[/tex]

We will solve the above equation using the following quadratic function formula:

[tex]t = \frac{1.53 + \sqrt{1.53^2 - 4(4.9)(-4.21)}}{2(4.9)}[/tex]

[tex]t \approx 1.10 ~ s[/tex]

Learn moreVelocity of Runner : https://brainly.com/question/3813437Kinetic Energy : https://brainly.com/question/692781Acceleration : https://brainly.com/question/2283922The Speed of Car : https://brainly.com/question/568302

Answer details

Grade: High School

Subject: Physics

Chapter: Kinematics

Keywords: Velocity , Driver , Car , Deceleration , Acceleration , Obstacle , Speed , Time , Rate

A monochromatic laser is exciting hydrogen atoms from the n=2 state to the n=5 state. part a what is the wavelength λ of the laser?

Answers

The energy levels of the hydrogen atom are given by
[tex]E_n=-13.6 \frac{1}{n^2} [eV] [/tex]
where n is the level number.

In order to make transition from n=2 state to n=5 state, the electron should acquire an energy equal to the difference between the two energy levels:
[tex]\Delta E= E_5 - E_2 = -13.6 \frac{1}{5^2}-(-13.6 \frac{1}{2^2})= -0.54+3.4=2.86 eV[/tex]

Keeping in mind that [tex]1 eV = 1.6 \cdot 10^{-19}eV[/tex], we can convert this energy in Joules
[tex]\Delta E = 2.86 eV \cdot 1.6 \cdot 10^{-19} J/eV=4.58 \cdot 10^{-19} J[/tex]

This is the energy the photons of the laser should have in order to excite electrons from n=2 state to n=5 state. Their frequency can be found by using
[tex]\Delta E=hf[/tex]
where h is the Planck constant and f is the photon frequency. Re-arranging it, we find
[tex]f= \frac{\Delta E}{h}= \frac{4.58 \cdot 10^{-19} J}{6.6 \cdot 10^{-34} Js}=6.94 \cdot 10^{14} Hz [/tex]

and finally we can use the relationship between frequency, wavelength and speed of light which holds for photons, in order to find their wavelength:
[tex]\lambda= \frac{c}{f}= \frac{3 \cdot 10^8 m/s}{6.94 \cdot 10^{14} Hz}=4.32 \cdot 10^{-7} m =432 nm [/tex]
and this is the laser wavelenghth.

Discuss five ways human activity has accelerated soil erosion

Answers

Answer:

road erosion, house construction, steep slope cultivation, tourism development, and animal trampling.

Explanation:

In a typical lightning strike, 2.9 c flows from cloud to ground in 0.18 ms. what is the current during the strike?

Answers

Current = (charge) / (time)

= (2.9 C) / (0.18 ms)

= (2.9 C) / (0.00018 sec)

16,111 Amperes !  (but it doesn't last long)


Find the kinetic energy of an electron whose de broglie wavelength is 34.0 nm.

Answers

The De Broglie wavelength of the electron is
[tex]\lambda=34.0 nm=34 \cdot 10^{-9} m[/tex]
And we can use De Broglie's relationship to find its momentum:
[tex]p= \frac{h}{\lambda}= \frac{6.6 \cdot 10^{-34} Js}{34 \cdot 10^{-9} m}=1.94 \cdot 10^{-26} kg m/s [/tex]

Given [tex]p=mv[/tex], with m being the electron mass and v its velocity, we can find the electron's velocity:
[tex]v= \frac{p}{m}= \frac{1.94 \cdot 10^{-26} kgm/s}{9.1 \cdot 10^{-31} kg}= 2.13 \cdot 10^4 m/s[/tex]

This velocity is quite small compared to the speed of light, so the electron is non-relativistic and we can find its kinetic energy by using the non-relativistic formula:
[tex]K= \frac{1}{2}mv^2= \frac{1}{2}(9.1 \cdot 10^{-31} kg)(2.13 \cdot 10^4 m/s)^2=2.06 \cdot 10^{-22} J [/tex]

Kinetic energy is a property of a moving item that is affected by both mass and velocity. The electron's kinetic energy with a de-Broglie wavelength of 34nm is 2.06 × [tex]10^-^2^2[/tex]J.

First, we have to convert de Broglie wavelength in m to satisfy the dimensions.

λ = 34.0nm =34×[tex]10^-^9[/tex].

To find  kinetic energy we need to find velocity and for that, we need to find momentum by using the formulae:

P= h/λ  = 6.6×[tex]10^-^3^4[/tex]/34×[tex]10^-^9[/tex] = 1.94×[tex]10^-^2^6[/tex] kgm/s.

After getting momentum we need to find the velocity

V=p/m = 1.94×[tex]10^-^2^6[/tex] / 9.1×[tex]10^-^3^1[/tex]= 2.13×[tex]10^4[/tex] m/s.

Now we have the value of velocity and by applying it  [tex]k=1/2mv^2[/tex], we can find easily find the kinetic energy

[tex]k=1/2mv^2[/tex] = 1/2 (9.1×[tex]10^-^3^1[/tex] kg)×(2.13×[tex]10^4[/tex] m/s[tex])^2[/tex] = 2.06×[tex]10^-^2^2[/tex]J.

Therefore, the kinetic energy of the particle is 2.06×[tex]10^-^2^2[/tex]J.

To know more about energy refer to:

https://brainly.com/question/8630757

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