1. Test question 7.1 • In the solar system, the temperature difference between terrestrial planets and gas giants is due to • vTheir distance from the sun, • xThe number of their moons • xThe length of their days • xTilt of their spin

2. Test question 7.2 • Laplace’s nebula hypothesis suggests that planets in the solar system formed • xThrough capture of freely floating planets, B) xOut a piece of the sun which was torn out, from the Sun by a passing star, C) vIn a gaseous disk surrounding the infant Sun, D) xFrom the left over of its companion

3. Test question 7.3 When a molecular cloud collapses and shrinks its radius to 0.001 times of its original size, its spin rate would become • vFaster by a million times, • xFaster by a thousand times • xStay the same • xSlow down by a thousand times

4. Test question 7.4 Mercury orbits the Sun at 0.4 AU whereas Pluto’s distance is 40 AU. If there were formed at the present-day location, temperature due to the solar irradiation at Mercury would be: • x100 times hotter than at Pluto • v10 times hotter than at Pluto • xSame as at Pluto • x100 times cooler than at Pluto

5. Test question 7.5 • Radioactive CAI’s in primitive meteorites provide constraints on • xThe dominant chemical composition of the solar nebula • vTime scale for solar system formation • xThe rate of nuclear energy release from the Sun • xPlanet formation through core accretion

6. Test question 7.6 • The half life of radioactive C14 is 5760 years. In 17,280 years after one gram of C14 was generated, the amount of it left behind is • xHalf its original amount, • xOne third of its original amount, • xOne quarter of its original amount, • vOne eighth of its original amount.

7. Test question 7.7 Dense Craters on the moon and mercury indicate: • xTerrestrial planets had many volcano when they were young • vThese objects formed through collisions & impacts • xAll terrestrial planets cool down rapid after their formation • xPlate tectonics is active in these planets.