Match each scientist with his major discovery or contribution. 1. ernest rutherford discovery of the electron 2. james chadwick discovery of the neutron 3. henri becquerel discovery of the atomic nucleus 4. j. j. thomson discovery of radioactivity

Identify the correct relation showing that the radius r of the orbit of a moon of a given planet can be determined from the radius r of the planet, the acceleration of gravity at the surface of the planet, and the time τ required by the moon to complete one full revolution about the planet. determine the acceleration of gravity at the surface of the planet jupiter knowing that r = 71 492 km and that t= 3.551 days and r= 670.9 × 10^3 km for its moon europa.