1. The sun produces 3.826 x 10^26 Joules of energy every second as it combines smaller hydrogen atoms into larger helium atoms. What is the name of the process which allows for the production of so much energy?
A) fission

B) fusion

C) heation

D) photosynthesis

2. Thorium-229 is the radioactive substance that gives lantern mantels their eerie glow. The half life of thorium-229 is 7340 years. If one mantel consists of 0.25 grams of thorium, how much thorium will remain after 14,680 years?
A) 0.0625g

B) 0.125g

C) 0.25g

D) 1.0g

Question

1. The sun produces 3.826 x 10^26 Joules of energy every second as it combines smaller hydrogen atoms into larger helium atoms. What is the name of the process which allows for the production of so much energy?
A) fission

B) fusion

C) heation

D) photosynthesis

2. Thorium-229 is the radioactive substance that gives lantern mantels their eerie glow. The half life of thorium-229 is 7340 years. If one mantel consists of 0.25 grams of thorium, how much thorium will remain after 14,680 years? 
A) 0.0625g

B) 0.125g

C) 0.25g 

D) 1.0g

anonymous · Answer

1. we are "combining smaller things into bigger things", does it sound like "fusion" or "fission"?

2. say we start with one gram of radioactive isotope whose half life is one second. how much of the radioactive isotope is left after one second? how much remains after two seconds?