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.
The gravitational field strength at a point X in a gravitational field is defined as the force
The graphs A to D below are plots of against in arbitrary units.
Which one of the graphs best represents the variation of , the electrostatic potential due to a positive point charge, with , the distance from the point charge?
The two graphs below represent the variation with distance, , for to of the electric field and the electric potential around an isolated point charge.
Graph 1:
Graph 2:
The work done by an external force in moving a test charge from to is equal to multiplied by the
A communications satellite is moving at a constant speed in a circular orbit around Earth. At any given instant in time, the resultant force on the satellite is
A small positively charged sphere is moved between two points and that are between two parallel charged plates. Three paths between and are shown.
Which statement is correct?
A student blows across the top of a cylinder that contains water. A first-harmonic standing sound wave is produced in the air of the cylinder. More water is then added to the cylinder. The student blows so that a first-harmonic standing wave is produced with a different frequency.
What is the nature of the displacement in the air at the water surface and the change in frequency when the water is added?
Nature of displacement | Change in frequency | |
---|---|---|
A. | antinode | decrease |
B. | antinode | increase |
C. | node | decrease |
D. | node | increase |
and are two points on a gravitational equipotential surface around a planet. and are two points on a different gravitational equipotential surface at a greater distance from the planet.
The greatest work done by the gravitational force is when moving a mass from
Two isolated spheres of masses and are held a distance apart, as shown below.
Mass is greater than mass .
The gravitational field strength is measured on a line between the two masses. Which graph best shows the variation with distance from the larger sphere of the magnitude of the field strength ? The Earth's gravitational field is to be ignored.
A satellite orbits the Earth as shown below.
In the table below, which row gives the correct sign for the satellite's potential and kinetic energies?
Potential energy | Kinetic energy |
---|---|
Positive | Positive |
Negative | Positive |
Positive | Negative |
Negative | Negative |