This question is in two parts. Part 1 is about energy sources and the greenhouse effect. Part 2 is about gravitational potential.
Nuclear fuels, unlike fossil fuels, produce no greenhouse gases. Identify two greenhouse gases.
Discuss, with reference to the mechanism of infrared absorption, why the temperature of the Earth's surface would be lower if there were no greenhouse gases present in the atmosphere.
State one advantage of power production using fossil fuels compared to using nuclear fuels.
Outline the reason why fuel enrichment is necessary for the fuel used in a commercial nuclear reactor.
A domestic water tank contains 620 kg of water. You are asked to compare raising the temperature of the water by 25 K using the energy available from nuclear fission and the energy available from the Sun. The following data are available. Energy density of uranium-235 = 2.0 × 10^13 J kg^-1, Area of solar panels used = 23 m^2, Average solar power during daylight = 0.74 kW m^-2, Specific heat capacity of water = 4.2 × 10^3 J kg^-1 K^-1. Determine the mass of uranium-235 that is needed to raise the temperature of the water by 25 K.
Determine the time in hours required to raise the temperature of the water by 25 K using the solar panels.
The solar energy in is used to heat the water directly, whereas the nuclear energy must first be converted into electrical energy in the nuclear power station. Outline the energy transformations that take place within the nuclear power station in the production of electrical power.
Define gravitational potential at a point in a gravitational field.
The graph shows how the gravitational potential V of Earth varies with distance R from the centre of Earth in the range R = 2.0 × 10^8 m to R = 5.0 × 10^8 m. The Moon is at a distance of 4.0 × 10^8 m from the centre of Earth. At some time in the past it was at a distance of 2.7 × 10^8 m from the centre of Earth. Use the graph to determine the present day magnitude of the acceleration of the Moon.
Use the graph to determine by how much the potential energy of the Moon has changed as a result of moving from R = 2.7 × 10^8 m to R = 4.0 × 10^8 m. The mass of the Moon is 7.4 × 10^22 kg.
State why the change of potential energy in (f)(ii) is an increase.
Which of the following is true when thermal energy is converted into work in a single process and a cyclical process?
Single process | Cyclical process | |
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A. | complete conversion of thermal energy into work can occur | energy must be transferred from the system |
B. | complete conversion of thermal energy into work can never occur | energy must be transferred from the system |
C. | complete conversion of thermal energy into work can occur | energy need not be transferred from the system |
D. | complete conversion of thermal energy into work can never occur | energy need not be transferred from the system |
Methane and carbon dioxide are both greenhouse gases that are believed to cause global warming. The reason for this is that these gases
Three energy sources for power stations are
Which energy sources are primary sources?
The orbital radius of the Earth around the Sun is 1.5 times that of Venus. What is the intensity of solar radiation at the orbital radius of Venus?
The average temperature of the surface of a planet is five times greater than the average temperature of the surface of its moon. The emissivities of the planet and the moon are the same. The average intensity radiated by the planet is . What is the average intensity radiated by its moon?
Which of the following gives the approximate ratio of the separation of the molecules in water and in steam at atmospheric pressure?
Water : Steam |
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Which change produces the largest percentage increase in the maximum theoretical poweroutput of a wind turbine?
This question is about fuel for heating.
Define the energy density of a fuel.
A room heater burns liquid fuel and the following data are available.
Density of liquid fuel = 8.0 × 10² kg m⁻³ Energy produced by 1 m³ of liquid fuel = 2.7 × 10¹⁰ J Rate at which fuel is consumed = 0.13 g s⁻¹ Temperature at which air enters heater = 12°C Temperature at which air leaves heater = 32°C Specific heat capacity of air = 990 J kg⁻¹ K⁻¹
Use the data to calculate the power output of the room heater, ignoring the power required to convert the liquid fuel into a gas.
All the energy output of the room heater raises the temperature of the air moving through it. Use the data to calculate the mass of air that moves through the room heater in one second.
The greenhouse effect can be explained by the fact that the infrared radiation emitted by the surface of Earth