Gravitational Forces, Planetary Orbits, and Radiation: A Comprehensive Study, Exams of Physics

Download Gravitational Forces, Planetary Orbits, and Radiation: A Comprehensive Study and more Exams Physics in PDF only on Docsity! PSU Astro 7N Midterm Exam With 100% Correct Answers 2024 According to Newton's 2nd law of motion, if the net force acting on the object increases while the mass of the object remains constant, what happens to the acceleration? - Correct Answer-Acceleration increases If Each were moved to half its current distance from the sun how would the force of gravity by the sun on Earth change? - Correct Answer-4x stronger what did Newton's Law of Universal Gravitation tell us about how gravity works? - Correct Answer-The force of gravity will be stronger on an object with more mass The Earth radius is about 6400 km. If you were in orbit in the space station 150km above the ground, the force of gravity you feel from Earth would be - Correct Answer-slightly weaker than when you are standing on Earth If you were to sit on the ground, there would be a force due to gravity pulling you toward the Earth. Which of the following is true according to Newton's 3rd law? - Correct Answer-You are pushing the Earth away from yourself with the same force What would happen to the Earth if the sun's gravity somehow "turned off" instantaneously? - Correct Answer-It would continue to move in a line in the same direction it was moving when gravity turned off Consider a planet whose rotation axis is NOT titled with respect to its orbital plane. What are these seasons like on this planet? - Correct Answer-There are no seasons If the Earth rotated on its axis more slowly than it does now: - Correct Answer-Days would be longer If Earth had its orbit changed so that all points along its orbit were always the same distance from the sun(circular orbit), how would this affect the seasons on Earth? - Correct Answer- They would be the same as they are now A new planet orbits its star faster than the Earth orbits the sun and it rotates more slowly than the Earth rotates. Which of What is the relationship between wavelength and frequency? - Correct Answer-If the frequency increases, wavelength decreases Compare the frequency of x-ray versus regular light - Correct Answer-The x-ray has a larger frequency than visible light Compare the frequency and wavelength of a gamma ray with that of visible light: - Correct Answer-Gamma ray frequency is higher and its wavelength is lower Compared to blue light, red light has - Correct Answer-Longer wavelength, smaller frequency, smaller energy Which types of radiation have the lowest energy? - Correct Answer-Infrared radiation and radio The spectrum of an oxygen lamp looks different than the spectrum of a sodium lamp because: - Correct Answer-Each atom has a unique set of electron orbits Dark lines in an absorption spectrum represent: - Correct Answer-Particular energies of light coming from a distant object that are absorbed by material in between True or false: The energy of a photon increases in proportion to the wavelength of the radiation - Correct Answer-False True or false: An absorption spectrum appears as a continuous spectrum interrupted by a series of dark lines - Correct Answer-True The electrons in a cloud of hydrogen gas are making the transition from excited states to the ground state. What does the spectrum of this cloud of gas look like? - Correct Answer-It will consist of few bright emission lines at specific wavelengths In what ways does a 30 meter telescope outperform a 10 meter telescope? - Correct Answer-Its images are 9x brighter than a 10 meter Even the largest ground-based telescopes have resolution restrictions imposed by: - Correct Answer-Atmospheric blurring of images When you magnify an object with a telescope, what else happens to your view of the sky? - Correct Answer-Your field of view gets smaller, so you can only see a small area of the sky How long would one need to observe a star on a 10 meter telescope to collect the same amount of light as one collects in one hour on a 5 meter telescope? - Correct Answer-15 minutes If a telescope in space is only 1/4 the diameter of a telescope on Earth, is this statement true or false: the larger telescope can observe objects fainter that the space telescope - Correct Answer-True What was Kepler's first law? - Correct Answer-Planets revolve around the sun in elliptical orbits with the sun at one focus of the ellipse Volcanoes on Venus: - Correct Answer-produce very large lava flows that cover at least 85% of the planet's surface Where do mountains on Earth come from? - Correct Answer- In some locations, plates of rock on the planet's surface press together and the plates rise together Where are aurorae likely to be seen most frequently? - Correct Answer-At locations near the poles What is NOT true about Earth's atmosphere - Correct Answer- It has more carbon dioxide than Venus, so is heated more than Venus by the Greenhouse effect What us ozone? - Correct Answer-3 oxygen atoms bonded together in a single molecule What would happen if the ozone layer were completely destroyed? - Correct Answer-UV radiation from the sun would get through the atmosphere and cause damage to life Why is Venus's day so long (a day-night cycle on Venus lasts for as long as 243 Earth day and night cycles)? - Correct Answer-Venus's rotation time is very long compared to the time it takes to go once around the sun The Greenhouse effect: - Correct Answer-Is larger on Venus than on Earth The densities of the four Terrestrial planets are similar to each other. This means - Correct Answer-They are made of similar substances A meteor shower can occur when: - Correct Answer-Earth's orbit crosses a trail of debris left behind from a comet Most meteors: - Correct Answer-Are very small pieces of rock burning in the Earth's atmosphere A comet's nucleus is composed of: - Correct Answer-Dust, dry ice, and water ice The material in a meteorite is: - Correct Answer-Roughly as old as the solar system What causes day and night? - Correct Answer-Rotation of the Earth on its axis How does the Sun appear to move in the sky in the course of a day? - Correct Answer-East to West, because of Earth's rotation. The stars and planets move in the same way from our point of view, also, because of Earth's rotation What happens to the Earth in one year? - Correct Answer-It orbits the Sun, once (also referred to as one complete revolution about the Sun) Why do we have seasons? - Correct Answer-The tilt of the Earth's axis of rotation, with respect to the plane of its orbit around the Sun (and not because of changing distance from Sun). The Earth's tilt is about 23 degrees How is the Earth's axis tilted when we have summer in the Northern hemisphere? - Correct Answer-With the North pole toward the Sun Why do eclipses not occur every month on Earth? - Correct Answer-The Moon orbits the Earth in a slightly different plane than the Earth orbits the Sun What about eclipses of the moons of Mars? - Correct Answer- Mars has two small moons, Phobos and Deimos. Relative to Earth's Moon, they are tiny, and closer to their planet and orbiting faster — and closer to the orbital plane of Mars around the Sun. This leads to more frequent eclipses visible from Mars What does ecliptic mean? - Correct Answer-The apparent path of the Sun over the course of a year, with respect to the distant stars What are the forms of light in order from highest to lowest energies? - Correct Answer-Gamma ray, x-ray, ultraviolet, visible, infrared, microwave, radio What is a photon - Correct Answer-A particle of light Describe a bluer color light in terms of its energy, frequency, and wavelength - Correct Answer-High-energy light, high frequency, low/short wavelength Describe a redder color light in terms of its energy, frequency, and wavelength - Correct Answer-Low-energy light, low frequency, high/long wavelength What kinds of radiation get through the Earth's atmosphere? - Correct Answer-Visible and radio What is a continuum spectrum? - Correct Answer-Light at all wavelengths What is an absorption spectrum? - Correct Answer-Shows absorption lines, dark lines in the spectrum at certain wavelengths, superimposed on a continuum spectrum and produced by a (less-energetic) gas cloud in front of a light source What is an emission spectrum? - Correct Answer-Shows emission lines, bright lines at specific wavelengths, in an otherwise empty (dark) spectrum, due to emission of photons from atoms in gas that have electrons in elevated levels Reflecting telescopes use what to collect focus and light? - Correct Answer-A mirror Refracting telescopes use what to collect focus and light? - Correct Answer-A lens How many astronomical units are between the Earth and the Sun? - Correct Answer-1 What two properties of a planet affect the gravity we feel on its surface? - Correct Answer-Mass and radius Two planets have the same radius. If Planet A is 5 times more massive than Planet B, how does gravity differ on the surfaces of the two planets? - Correct Answer-Gravity is 5 times stronger on Planet A Say that there were a Planet X in our Solar System with a mass 1/4 the mass of Earth and a radius 1/2 the radius or Earth. How will the gravity on its surface compare to the surface A star is a hot, dense gas surrounded by a cooler, low density atmosphere. What type of spectrum will a star create? - Correct Answer-Absorption spectrum What makes a transition from a lower energy state to a higher energy state when a photon is absorbed into an atom? - Correct Answer-Electron An emission line is produced when: - Correct Answer-An electron passes from a higher to a lower energy level Bright lines in an emission spectrum represent: - Correct Answer-Particular energies of light that are emitted from a distant object The faintness of an object that a telescope can observe is mostly determined by... - Correct Answer-The diameter of the opening of the telescope In what ways does a 5 meter telescope outperform a 1 meter telescope? - Correct Answer-Its images are 25 times brighter than a 1 meter A mountain top is a good location for optical telescopes because the site... - Correct Answer-Is above much of the atmosphere True or false: Venus rotates in the opposite direction from the three other inner planets - Correct Answer-True True or false: Mercury rotates exactly one and a half times for every one revolution around the Sun - Correct Answer-True Why do the orbits of the planets all lie in nearly the same plane? - Correct Answer-The early solar nebula flattened into a disk A planet is in orbit around the Sun. The semimajor axis of the orbit is 5 Astronomical Units (AU). Use P^2 = a^3 to calculate the period of the orbit, in years. - Correct Answer-11.2 years Venus is visible to us... - Correct Answer-Only near sunrise or sunset How do most craters on moons form? - Correct Answer- Impact of asteroids Which planet has a temperature of 800 degrees Fahrenheit on the side facing the Sun and -290 degrees Fahrenheit on the side opposite the Sun? - Correct Answer-Mercury How many Earth years does it take Uranus to orbit the Sun? - Correct Answer-84 Meteors are... - Correct Answer-Asteroids or comet debris that passes into Earth's atmosphere and burns up Which feature of Neptune is most responsible for its blue color? - Correct Answer-Methane in its atmosphere True or false: The planet Saturn has more than 30 moons - Correct Answer-True The surface of Venus is hotter than the surface of Mercury because - Correct Answer-Venus is more massive and is able to retain a thick atmosphere