Foram encontradas 60 questões.
Ao emitir uma partícula alfa, o isótopo de polônio !$ ^{210}_{84} !$Po se transforma em:
Provas
Uma máquina opera entre duas fontes, em temperaturas iguais a 400 K e a 300 K. Em um ciclo, o calor absorvido na fonte é 100 J, e o trabalho produzido é 15 J.
Se essa máquina se tornasse reversível e trabalhasse entre as mesmas temperaturas e com o mesmo calor absorvido, qual seria o aumento de trabalho produzido por ciclo, em J?
Provas
Durante um ciclo termodinâmico de uma máquina, o gás (substância de trabalho) recebe 100 J de calor de uma fonte quente a TQ = 500 K e rejeita 75 J de calor em uma fonte fria a TF = 300 K. Cada ciclo dura 1,0 ms.
Com relação ao rendimento da máquina, considere as afirmativas abaixo:
I - O rendimento do ciclo é igual a 1/3.
II - O ciclo é irreversível, produzindo a cada ciclo !$ \Delta !$Sciclo = 0,05 J/K de entropia.
III - A potência produzida pela máquina é 25 kW.
É verdadeiro APENAS o que se afirma em:
Provas
Seja um fluido de coeficiente de expansão térmica desprezível comparado ao coeficiente linear de dilatação térmica !$ \lambda !$ da tubulação cilíndrica que o contém. Esse fluido, em uma temperatura T, flui com uma velocidade V ao longo da tubulação. Suponha que o fluido e a tubulação tenham sua temperatura elevada para T + !$ \Delta !$T, mas que agora a velocidade do fluido é V + !$ \Delta !$V.
Sabendo-se que o mesmo fluxo volumétrico de fluido passa pela tubulação para as duas temperaturas, a razão !$ \Delta !$V/V, em função de !$ \Delta !$T e !$ \lambda !$, é
Provas
Três folhas metálicas quadradas idênticas A, B e C, paralelas, finas e de lado muito maior que as distâncias entre elas, estão em um estado estacionário de temperatura devido à radiação, sendo TA = T0 e TC = 2 T0. A folha metálica B é a que fica entre as folhas A e C.
A temperatura estacionária TB é
Provas
Disciplina: Inglês (Língua Inglesa)
Banca: CESGRANRIO
Orgão: Eletronuclear
The controversial future of nuclear power in the U.S.
Lois Parshley
President Joe Biden has set ambitious goals for fighting climate change: To cut U.S. carbon emissions in half by 2030 and to have a net-zero carbon economy by 2050. The plan requires electricity generation – the easiest economic sector to green, analysts say – to be carbon-free by 2035.
A few figures from the U.S. Energy Information Administration (EIA) illustrate the challenge. In 2020 the United States generated about four trillion kilowatt-hours of electricity. Some 60 percent of that came from burning fossil fuels, mostly natural gas, in some 10,000 generators, large and small, around the country. All of that electricity will need to be replaced - and more, because demand for electricity is expected to rise, especially if we power more cars with it.
Renewable energy sources like solar and wind have grown faster than expected; together with hydroelectric, they surpassed coal for the first time ever in 2019 and now produce 20 percent of U.S. electricity. In February the EIA projected that renewables were on track to produce more than 40 percent by 2050 - remarkable growth, perhaps, but still well short of what’s needed to decarbonize the grid by 2035 and forestall the climate crisis.
This daunting challenge has recently led some environmentalists to reconsider an alternative they had long been wary of: nuclear power.
Nuclear power has a lot going for it. Its carbon footprint is equivalent to wind, less than solar, and orders of magnitude less than coal. Nuclear power plants take up far less space on the landscape than solar or wind farms, and they produce power even at night or on calm days. In 2020 they generated as much electricity in the U.S. as renewables did, a fifth of the total.
But debates rage over whether nuclear should be a big part of the climate solution in the U.S. The majority of American nuclear plants today are approaching the end of their design life, and only one has been built in the last 20 years. Nuclear proponents are now banking on next-generation designs, like small, modular versions of conventional light-water reactors, or advanced reactors designed to be safer, cheaper, and more flexible.
“We’ve innovated so little in the past half-century, there’s a lot of ground to gain,” says Ashley Finan, the director of the National Reactor Innovation Center at the Idaho National Laboratory. Yet an expansion of nuclear power faces some serious hurdles, and the perennial concerns about safety and long-lived radioactive waste may not be the biggest: Critics also say nuclear reactors are simply too expensive and take too long to build to be of much help with the climate crisis.
While environmental opposition may have been the primary force hindering nuclear development in the 1980s and 90s, now the biggest challenge may be costs. Few nuclear plants have been built in the U.S. recently because they are very expensive to build here, which makes the price of their energy high.
Jacopo Buongiorno, a professor of nuclear science and engineering at MIT, led a group of scientists who recently completed a two-year study examining the future of nuclear energy in the U.S. and western Europe. They found that “without cost reductions, nuclear energy will not play a significant role” in decarbonizing the power sector.
“In the West, the nuclear industry has substantially lost its ability to build large plants,” Buongiorno says, pointing to Southern Company’s effort to add two new reactors to Plant Vogtle in Waynesboro, Georgia. They have been under construction since 2013, are now billions of dollars over budget - the cost has more than doubled - and years behind schedule. In France, ranked second after the U.S. in nuclear generation, a new reactor in Flamanville is a decade late and more than three times over budget.
“We have clearly lost the know-how to build traditional gigawatt-scale nuclear power plants,” Buongiorno says. Because no new plants were built in the U.S. for decades, he and his colleagues found, the teams working on a project like Vogtle haven’t had the learning experiences needed to do the job efficiently. That leads to construction delays that drive up costs.
Elsewhere, reactors are still being built at lower cost, “largely in places where they build projects on budget, and on schedule,” Finan explains. China and South Korea are the leaders. (To be fair, several of China’s recent large-scale reactors have also had cost overruns and delays.)
“The cost of nuclear power in Asia has been a quarter, or less, of new builds in the West,” Finan says. Much lower labor costs are one reason, according to both Finan and the MIT report, but better project management is another.
Available at: https://www.nationalgeographic.com/environment/ article/nuclear-plants-are-closing-in-the-us-should-we-build-more. Retrieved on: Feb. 3, 2022. Adapted.
In the last paragraph, the author states that “Much lower labor costs are one reason, according to both Finan and the MIT report, but better project management is another.” because he believes that
Provas
Disciplina: Inglês (Língua Inglesa)
Banca: CESGRANRIO
Orgão: Eletronuclear
The controversial future of nuclear power in the U.S.
Lois Parshley
President Joe Biden has set ambitious goals for fighting climate change: To cut U.S. carbon emissions in half by 2030 and to have a net-zero carbon economy by 2050. The plan requires electricity generation – the easiest economic sector to green, analysts say – to be carbon-free by 2035.
A few figures from the U.S. Energy Information Administration (EIA) illustrate the challenge. In 2020 the United States generated about four trillion kilowatt-hours of electricity. Some 60 percent of that came from burning fossil fuels, mostly natural gas, in some 10,000 generators, large and small, around the country. All of that electricity will need to be replaced - and more, because demand for electricity is expected to rise, especially if we power more cars with it.
Renewable energy sources like solar and wind have grown faster than expected; together with hydroelectric, they surpassed coal for the first time ever in 2019 and now produce 20 percent of U.S. electricity. In February the EIA projected that renewables were on track to produce more than 40 percent by 2050 - remarkable growth, perhaps, but still well short of what’s needed to decarbonize the grid by 2035 and forestall the climate crisis.
This daunting challenge has recently led some environmentalists to reconsider an alternative they had long been wary of: nuclear power.
Nuclear power has a lot going for it. Its carbon footprint is equivalent to wind, less than solar, and orders of magnitude less than coal. Nuclear power plants take up far less space on the landscape than solar or wind farms, and they produce power even at night or on calm days. In 2020 they generated as much electricity in the U.S. as renewables did, a fifth of the total.
But debates rage over whether nuclear should be a big part of the climate solution in the U.S. The majority of American nuclear plants today are approaching the end of their design life, and only one has been built in the last 20 years. Nuclear proponents are now banking on next-generation designs, like small, modular versions of conventional light-water reactors, or advanced reactors designed to be safer, cheaper, and more flexible.
“We’ve innovated so little in the past half-century, there’s a lot of ground to gain,” says Ashley Finan, the director of the National Reactor Innovation Center at the Idaho National Laboratory. Yet an expansion of nuclear power faces some serious hurdles, and the perennial concerns about safety and long-lived radioactive waste may not be the biggest: Critics also say nuclear reactors are simply too expensive and take too long to build to be of much help with the climate crisis.
While environmental opposition may have been the primary force hindering nuclear development in the 1980s and 90s, now the biggest challenge may be costs. Few nuclear plants have been built in the U.S. recently because they are very expensive to build here, which makes the price of their energy high.
Jacopo Buongiorno, a professor of nuclear science and engineering at MIT, led a group of scientists who recently completed a two-year study examining the future of nuclear energy in the U.S. and western Europe. They found that “without cost reductions, nuclear energy will not play a significant role” in decarbonizing the power sector.
“In the West, the nuclear industry has substantially lost its ability to build large plants,” Buongiorno says, pointing to Southern Company’s effort to add two new reactors to Plant Vogtle in Waynesboro, Georgia. They have been under construction since 2013, are now billions of dollars over budget - the cost has more than doubled - and years behind schedule. In France, ranked second after the U.S. in nuclear generation, a new reactor in Flamanville is a decade late and more than three times over budget.
“We have clearly lost the know-how to build traditional gigawatt-scale nuclear power plants,” Buongiorno says. Because no new plants were built in the U.S. for decades, he and his colleagues found, the teams working on a project like Vogtle haven’t had the learning experiences needed to do the job efficiently. That leads to construction delays that drive up costs.
Elsewhere, reactors are still being built at lower cost, “largely in places where they build projects on budget, and on schedule,” Finan explains. China and South Korea are the leaders. (To be fair, several of China’s recent large-scale reactors have also had cost overruns and delays.)
“The cost of nuclear power in Asia has been a quarter, or less, of new builds in the West,” Finan says. Much lower labor costs are one reason, according to both Finan and the MIT report, but better project management is another.
Available at: https://www.nationalgeographic.com/environment/ article/nuclear-plants-are-closing-in-the-us-should-we-build-more. Retrieved on: Feb. 3, 2022. Adapted.
In paragraph 12, the author affirms “(To be fair, several of China’s recent large-scale reactors have also had cost overruns and delays)”, in order to
Provas
Disciplina: Inglês (Língua Inglesa)
Banca: CESGRANRIO
Orgão: Eletronuclear
The controversial future of nuclear power in the U.S.
Lois Parshley
President Joe Biden has set ambitious goals for fighting climate change: To cut U.S. carbon emissions in half by 2030 and to have a net-zero carbon economy by 2050. The plan requires electricity generation – the easiest economic sector to green, analysts say – to be carbon-free by 2035.
A few figures from the U.S. Energy Information Administration (EIA) illustrate the challenge. In 2020 the United States generated about four trillion kilowatt-hours of electricity. Some 60 percent of that came from burning fossil fuels, mostly natural gas, in some 10,000 generators, large and small, around the country. All of that electricity will need to be replaced - and more, because demand for electricity is expected to rise, especially if we power more cars with it.
Renewable energy sources like solar and wind have grown faster than expected; together with hydroelectric, they surpassed coal for the first time ever in 2019 and now produce 20 percent of U.S. electricity. In February the EIA projected that renewables were on track to produce more than 40 percent by 2050 - remarkable growth, perhaps, but still well short of what’s needed to decarbonize the grid by 2035 and forestall the climate crisis.
This daunting challenge has recently led some environmentalists to reconsider an alternative they had long been wary of: nuclear power.
Nuclear power has a lot going for it. Its carbon footprint is equivalent to wind, less than solar, and orders of magnitude less than coal. Nuclear power plants take up far less space on the landscape than solar or wind farms, and they produce power even at night or on calm days. In 2020 they generated as much electricity in the U.S. as renewables did, a fifth of the total.
But debates rage over whether nuclear should be a big part of the climate solution in the U.S. The majority of American nuclear plants today are approaching the end of their design life, and only one has been built in the last 20 years. Nuclear proponents are now banking on next-generation designs, like small, modular versions of conventional light-water reactors, or advanced reactors designed to be safer, cheaper, and more flexible.
“We’ve innovated so little in the past half-century, there’s a lot of ground to gain,” says Ashley Finan, the director of the National Reactor Innovation Center at the Idaho National Laboratory. Yet an expansion of nuclear power faces some serious hurdles, and the perennial concerns about safety and long-lived radioactive waste may not be the biggest: Critics also say nuclear reactors are simply too expensive and take too long to build to be of much help with the climate crisis.
While environmental opposition may have been the primary force hindering nuclear development in the 1980s and 90s, now the biggest challenge may be costs. Few nuclear plants have been built in the U.S. recently because they are very expensive to build here, which makes the price of their energy high.
Jacopo Buongiorno, a professor of nuclear science and engineering at MIT, led a group of scientists who recently completed a two-year study examining the future of nuclear energy in the U.S. and western Europe. They found that “without cost reductions, nuclear energy will not play a significant role” in decarbonizing the power sector.
“In the West, the nuclear industry has substantially lost its ability to build large plants,” Buongiorno says, pointing to Southern Company’s effort to add two new reactors to Plant Vogtle in Waynesboro, Georgia. They have been under construction since 2013, are now billions of dollars over budget - the cost has more than doubled - and years behind schedule. In France, ranked second after the U.S. in nuclear generation, a new reactor in Flamanville is a decade late and more than three times over budget.
“We have clearly lost the know-how to build traditional gigawatt-scale nuclear power plants,” Buongiorno says. Because no new plants were built in the U.S. for decades, he and his colleagues found, the teams working on a project like Vogtle haven’t had the learning experiences needed to do the job efficiently. That leads to construction delays that drive up costs.
Elsewhere, reactors are still being built at lower cost, “largely in places where they build projects on budget, and on schedule,” Finan explains. China and South Korea are the leaders. (To be fair, several of China’s recent large-scale reactors have also had cost overruns and delays.)
“The cost of nuclear power in Asia has been a quarter, or less, of new builds in the West,” Finan says. Much lower labor costs are one reason, according to both Finan and the MIT report, but better project management is another.
Available at: https://www.nationalgeographic.com/environment/ article/nuclear-plants-are-closing-in-the-us-should-we-build-more. Retrieved on: Feb. 3, 2022. Adapted.
According to Jacopo Buongiorno, one of the reasons why it is more expensive to build large nuclear plants in the West is that
Provas
Disciplina: Inglês (Língua Inglesa)
Banca: CESGRANRIO
Orgão: Eletronuclear
The controversial future of nuclear power in the U.S.
Lois Parshley
President Joe Biden has set ambitious goals for fighting climate change: To cut U.S. carbon emissions in half by 2030 and to have a net-zero carbon economy by 2050. The plan requires electricity generation – the easiest economic sector to green, analysts say – to be carbon-free by 2035.
A few figures from the U.S. Energy Information Administration (EIA) illustrate the challenge. In 2020 the United States generated about four trillion kilowatt-hours of electricity. Some 60 percent of that came from burning fossil fuels, mostly natural gas, in some 10,000 generators, large and small, around the country. All of that electricity will need to be replaced - and more, because demand for electricity is expected to rise, especially if we power more cars with it.
Renewable energy sources like solar and wind have grown faster than expected; together with hydroelectric, they surpassed coal for the first time ever in 2019 and now produce 20 percent of U.S. electricity. In February the EIA projected that renewables were on track to produce more than 40 percent by 2050 - remarkable growth, perhaps, but still well short of what’s needed to decarbonize the grid by 2035 and forestall the climate crisis.
This daunting challenge has recently led some environmentalists to reconsider an alternative they had long been wary of: nuclear power.
Nuclear power has a lot going for it. Its carbon footprint is equivalent to wind, less than solar, and orders of magnitude less than coal. Nuclear power plants take up far less space on the landscape than solar or wind farms, and they produce power even at night or on calm days. In 2020 they generated as much electricity in the U.S. as renewables did, a fifth of the total.
But debates rage over whether nuclear should be a big part of the climate solution in the U.S. The majority of American nuclear plants today are approaching the end of their design life, and only one has been built in the last 20 years. Nuclear proponents are now banking on next-generation designs, like small, modular versions of conventional light-water reactors, or advanced reactors designed to be safer, cheaper, and more flexible.
“We’ve innovated so little in the past half-century, there’s a lot of ground to gain,” says Ashley Finan, the director of the National Reactor Innovation Center at the Idaho National Laboratory. Yet an expansion of nuclear power faces some serious hurdles, and the perennial concerns about safety and long-lived radioactive waste may not be the biggest: Critics also say nuclear reactors are simply too expensive and take too long to build to be of much help with the climate crisis.
While environmental opposition may have been the primary force hindering nuclear development in the 1980s and 90s, now the biggest challenge may be costs. Few nuclear plants have been built in the U.S. recently because they are very expensive to build here, which makes the price of their energy high.
Jacopo Buongiorno, a professor of nuclear science and engineering at MIT, led a group of scientists who recently completed a two-year study examining the future of nuclear energy in the U.S. and western Europe. They found that “without cost reductions, nuclear energy will not play a significant role” in decarbonizing the power sector.
“In the West, the nuclear industry has substantially lost its ability to build large plants,” Buongiorno says, pointing to Southern Company’s effort to add two new reactors to Plant Vogtle in Waynesboro, Georgia. They have been under construction since 2013, are now billions of dollars over budget - the cost has more than doubled - and years behind schedule. In France, ranked second after the U.S. in nuclear generation, a new reactor in Flamanville is a decade late and more than three times over budget.
“We have clearly lost the know-how to build traditional gigawatt-scale nuclear power plants,” Buongiorno says. Because no new plants were built in the U.S. for decades, he and his colleagues found, the teams working on a project like Vogtle haven’t had the learning experiences needed to do the job efficiently. That leads to construction delays that drive up costs.
Elsewhere, reactors are still being built at lower cost, “largely in places where they build projects on budget, and on schedule,” Finan explains. China and South Korea are the leaders. (To be fair, several of China’s recent large-scale reactors have also had cost overruns and delays.)
“The cost of nuclear power in Asia has been a quarter, or less, of new builds in the West,” Finan says. Much lower labor costs are one reason, according to both Finan and the MIT report, but better project management is another.
Available at: https://www.nationalgeographic.com/environment/ article/nuclear-plants-are-closing-in-the-us-should-we-build-more. Retrieved on: Feb. 3, 2022. Adapted.
In the fragment of paragraph 7 “and the perennial concerns about safety and long-lived radioactive waste may not be the biggest”, may not be expresses a(n)
Provas
Disciplina: Inglês (Língua Inglesa)
Banca: CESGRANRIO
Orgão: Eletronuclear
The controversial future of nuclear power in the U.S.
Lois Parshley
President Joe Biden has set ambitious goals for fighting climate change: To cut U.S. carbon emissions in half by 2030 and to have a net-zero carbon economy by 2050. The plan requires electricity generation – the easiest economic sector to green, analysts say – to be carbon-free by 2035.
A few figures from the U.S. Energy Information Administration (EIA) illustrate the challenge. In 2020 the United States generated about four trillion kilowatt-hours of electricity. Some 60 percent of that came from burning fossil fuels, mostly natural gas, in some 10,000 generators, large and small, around the country. All of that electricity will need to be replaced - and more, because demand for electricity is expected to rise, especially if we power more cars with it.
Renewable energy sources like solar and wind have grown faster than expected; together with hydroelectric, they surpassed coal for the first time ever in 2019 and now produce 20 percent of U.S. electricity. In February the EIA projected that renewables were on track to produce more than 40 percent by 2050 - remarkable growth, perhaps, but still well short of what’s needed to decarbonize the grid by 2035 and forestall the climate crisis.
This daunting challenge has recently led some environmentalists to reconsider an alternative they had long been wary of: nuclear power.
Nuclear power has a lot going for it. Its carbon footprint is equivalent to wind, less than solar, and orders of magnitude less than coal. Nuclear power plants take up far less space on the landscape than solar or wind farms, and they produce power even at night or on calm days. In 2020 they generated as much electricity in the U.S. as renewables did, a fifth of the total.
But debates rage over whether nuclear should be a big part of the climate solution in the U.S. The majority of American nuclear plants today are approaching the end of their design life, and only one has been built in the last 20 years. Nuclear proponents are now banking on next-generation designs, like small, modular versions of conventional light-water reactors, or advanced reactors designed to be safer, cheaper, and more flexible.
“We’ve innovated so little in the past half-century, there’s a lot of ground to gain,” says Ashley Finan, the director of the National Reactor Innovation Center at the Idaho National Laboratory. Yet an expansion of nuclear power faces some serious hurdles, and the perennial concerns about safety and long-lived radioactive waste may not be the biggest: Critics also say nuclear reactors are simply too expensive and take too long to build to be of much help with the climate crisis.
While environmental opposition may have been the primary force hindering nuclear development in the 1980s and 90s, now the biggest challenge may be costs. Few nuclear plants have been built in the U.S. recently because they are very expensive to build here, which makes the price of their energy high.
Jacopo Buongiorno, a professor of nuclear science and engineering at MIT, led a group of scientists who recently completed a two-year study examining the future of nuclear energy in the U.S. and western Europe. They found that “without cost reductions, nuclear energy will not play a significant role” in decarbonizing the power sector.
“In the West, the nuclear industry has substantially lost its ability to build large plants,” Buongiorno says, pointing to Southern Company’s effort to add two new reactors to Plant Vogtle in Waynesboro, Georgia. They have been under construction since 2013, are now billions of dollars over budget - the cost has more than doubled - and years behind schedule. In France, ranked second after the U.S. in nuclear generation, a new reactor in Flamanville is a decade late and more than three times over budget.
“We have clearly lost the know-how to build traditional gigawatt-scale nuclear power plants,” Buongiorno says. Because no new plants were built in the U.S. for decades, he and his colleagues found, the teams working on a project like Vogtle haven’t had the learning experiences needed to do the job efficiently. That leads to construction delays that drive up costs.
Elsewhere, reactors are still being built at lower cost, “largely in places where they build projects on budget, and on schedule,” Finan explains. China and South Korea are the leaders. (To be fair, several of China’s recent large-scale reactors have also had cost overruns and delays.)
“The cost of nuclear power in Asia has been a quarter, or less, of new builds in the West,” Finan says. Much lower labor costs are one reason, according to both Finan and the MIT report, but better project management is another.
Available at: https://www.nationalgeographic.com/environment/ article/nuclear-plants-are-closing-in-the-us-should-we-build-more. Retrieved on: Feb. 3, 2022. Adapted.
Based on the meanings in the text, the two items that express synonymous ideas are
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Caderno Container