Question 7 (4 points) Listen A scientist is studying the half-life of lithium-8 and after many years of study determined it's half-life to be approximately 0.84 seconds. Unfortunately, an intern has gotten the graph of lithium-8 mixed up with three other graphs. GraphA Graph B 12 09 073 1 123 15 179 2 2:25 23 273 Time Hell Graph C Graph D 10 20 30 41 30 50 70 10 The Idayal Time Idegty Identify the correct graph above for the decay of lithium-8. O Graph A O Graph B O Graph C O Graph DQuestion 8 (4 points) Listen Which type of radioactive decay produces particles with the highest energy? All produce the same energy particles Alpha O Gamma O BetaQuestion 9 (4 points) Listen Which of the following is a form of naturally-occurring radiation? O delta O fusion O sigma O beta fissionQuestion 10 (4 points) Listen Periodic Table of Elements 10 11 12 13 14 15 17 T1 Ci Cr Pm Eu DIET One radioactive substance is Carbon-14. How many neutrons exist in the nucleus of a Carbon-14 atom? 12 O 8 O 14 O 6Question 11 (4 points) Listen Strontium-90 (A#38) undergoes beta decay, which of the following equations accurately describes this. O 90 38 ST 90 38 Sr + By "ST 38 37 90 Rb + _je 38 O 90 38 ST 39Question 12 (4 points) Listen A student has an 80 g sample of a radioactive material that has a half-life of 20 seconds. How much material will he have left after one minute? 1.33 g 40 g O 5g C 10 g