Physics 3 Questions & Answers

Physics 3 Questions & Answers A 60-g sample of radioactive isotope is measured after two half-lives have passed. What pair of percentages describes the sample after two half-lives? - CORRECT ANSWER- 25% unchanged and 75% stable Calcium-51 has a half-life of 4.5 days. Only 0.75 gram remains of a sample that was initially 12 grams. How old is the sample of calcium-51? - CORRECT ANSWER- 18 days Carbon-14 is a radioactive element that undergoes beta decay. Which force is responsible for allowing carbon-14 to become stable? - CORRECT ANSWER- weak nuclear Compared to the weak nuclear force, the electromagnetic force - CORRECT ANSWER- is stronger Electromagnetic energy released during fusion is converted to other kinds of photons as it is transferred through which layer of the Sun? - CORRECT ANSWER- radiative zone Energy released by fusion in the Sun is initially in the form of - CORRECT ANSWER- gamma rays How are nuclear reactions used to meet the world's energy needs? - CORRECT ANSWERFission reactors are used to generate electricity, but fusion is not yet practical enough to be used How does gamma decay differ from both alpha decay and beta decay? - CORRECT ANSWERNo new element forms.