Q-1; The half-life of an isotope of an element is 5 days. The mass of a 10 gram sample of this isotope remaining after 20 days is:
1) 0.312 grams2) 0.625 grams3) 1.25 grams4) 2.50 gramsANSWER: 2 -- 0.625 GRAMS
Q-2; The idea that electrons revolved in orbits around the nucleus of an atom without radiating energy away from the atom was postulated by:
1) Thompson2) Bohr3) Rutherford4) EinsteinANSWER: 2 -- BOHR
Q-3; Alpha particles are nuclei of:
1) hydrogen2) helium3) oxygen4) nitrogenANSWER: 2 -- HELIUM
Q-4; A ball falling vertically from rest for 3 seconds travels very nearly:
1) 14.7 meters2) 29.4 meters3) 44.1 meters4) 88.2 metersANSWER: 3 -- 44.1 METERS
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