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Drupady [299]
4 years ago
5

A heat engine operates between 200 K and 100 K. In each cycle it takes 100 J from the hot reservoir, loses 25 J to the cold rese

rvoir, and does 75 J of work. This heat engine violates the second law but not the first law of thermodynamics. Why is this true?
Physics
1 answer:
Elena-2011 [213]4 years ago
6 0

Answer:

It does not violate the first law because the total energy taken is what is used 100J = 25J + 75J

But violates 2nd lawbecause the engine has a higher energy after doing work than the initial for e.g A cold object in contact with a hot one never gets colder, transferring heat to the hot object and making it hotter confirming the second law

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Diamond has a high index of refraction at about 2.4, which helps account for its sparkle. How fast does light travel through a d
wariber [46]

Answer:

1.25 \cdot 10^8 m/s

Explanation:

The speed of light through a medium is given by:

v=\frac{c}{n}

where

c = 3 \cdot 10^8 m/s is the speed of light through vacuum

n is the index of refraction of the material

In this case, diamond has a refractive index of n = 2.4, so the speed of light in diamond is

v=\frac{3\cdot 10^8 m/s}{2.4}=1.25\cdot 10^8 m/s

6 0
3 years ago
How does a coal-fired power plant use the energy in coal to produce electricity?
kakasveta [241]

Answer:

Answer is in explanation

Explanation:

A coal-fired power plant also known as steam power plant or thermal power plant is a generating station that converts heat energy of coal combustion into electrical energy. In a coal-fired power plant, steam coal, also known as thermal coal serves as the boiler's fuel.

Coal is collected, transported by road or rail to the power plant and stored in coal storage plant. Excess coal is stored in case of coal shortages, failure of transportation system, emergency outages or high electricity demand. From the coal storage plant, coal is fed to a crusher (or pulverizer or mill) through a conveyor. Inside the crusher, the coal is pulverized (crushed or milled) into fine powder. This increases the surface area and allows it to burn more quickly without using large quantity of hot air. The powdery coal is blown into the combustion chamber of a boiler then mixed with hot air where it is burnt at high temperature. After complete combustion of coal, ash produced is removed and  delivered to ash storage plant for disposal. The combustion reaction inside the boiler produces the heat energy needed to boil water in the pipes into steam at high temperature and pressure. The steam produced in the boiler is wet and is passed through a super-heater  where it is dried and super-heated.

The super-heated steam is passed into a steam turbine (containing thousands of propeller-like blades) through main valve. The heat energy from the steam is then converted to mechanical energy. The steam causes the turbine shaft to rotate at high speed by pushing the blades of the turbine. The rotating turbine drives the shaft of a generator mounted at one end of the turbine. Mechanical energy from the turbine is converted to electrical energy by the generator. When this generator is rapidly rotated in a strong magnetic field, electricity is generated. The electricity generated is stepped up into higher voltages and transmitted to power stations where it is stepped down into lower voltages for industrial and domestic usage. Steam exhausted  from the turbine is condensed by a condenser (natural or artificial). The condensed water from the condenser is fed back to the boiler to be heated once again as the cycle continues. This helps in improving the overall efficiency of the plant.

7 0
3 years ago
The induced magnetic field at radial distance 4.0 mm from the central axis of a circular parallel-plate capacitor is 1.8 ✕ 10−7
wel

Answer:

\frac{dE}{dt}=2.07*10^{13}\frac{V/m}{s}

Explanation:

According to Gauss's law, the electric flux through the circular plates is defined as the electric field multiplied by its area:

\Phi=EA=E(\pi R^2)(1)

The magnetic field around the varying electric field of the circular plates is given by:

B=\frac{\epsilon_0 \mu_o}{2\pi r}\frac{d\Phi}{dt}(2)

Replacing (1) in (2) and solving for \frac{dE}{dt}:

B=\frac{\epsilon_0 \mu_o\pi R^2}{2\pi r}\frac{dE}{dt}\\\frac{dE}{dt}=\frac{2rB}{\epsilon_0 \mu_o R^2}\\\frac{dE}{dt}=\frac{2(4*10^{-3}m)(1.8*10^{-7}T)}{(8.85*10^{-12}\frac{C^2}{N\cdot m^2})(4\pi *10{-7}\frac{Tm}{A})(2.5*10^{-3}m)^2}\\\\\frac{dE}{dt}=2.07*10^{13}\frac{V/m}{s}

3 0
3 years ago
Displacement vectors of 3 m and 5 m in the same direction combine to make a
n200080 [17]
Displacement vector that is 8 im magnitude
5 0
4 years ago
A segment is divided into two parts having lengths in the ratio of 5:3. If the difference between the length of the parts is 6",
Triss [41]

Answer:

15"

Explanation:

Let x be the length of the longer part, then the length of the shorter part is 3x/5, or also x - 6

therefore we have the following equation:

3x/5 = x - 6

We can multiply both sides by 5

3x = 5x - 6*5

2x = 30

x = 30/2 = 15"

So the length of the longer part is 15"

5 0
3 years ago
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