ch 6 energy

CHAPTER 6: Energy from Alternative Sources These questions cover Chapter 6 - all sections Total point value for this assignment = 30 pts (a combination of completion and correctness)

1. This nuclear equation represents a plutonium target being hit by an alpha particle. What do the superscripts numbers mean? (3pts)

+ ! [] ! +

a. What do the subscript numbers mean?

b. Show that the sum of the subscripts on the left and right of the arrow are equal to each other

2. Explain the significance of neutrons in initiating and sustaining the process of nuclear fission. In your answer define and use the term chain reaction. (3pts)

3. What percent of a radioactive isotope ( the parent) would remain after each of the following units of time has elapsed: (4pts)

a. One half life b. Two half lives c. Four half lives d. Six half lives

4. What percent of a radioactive isotope would have decayed (or been transformed) after each of the following units of time has elapsed: (4pts)

(looking for the amount that is the New daughter isotope) a. One half life b. Two half lives c. Four half lives d. Six half lives

5. In a nuclear power plant: (4pts) a. Why must the fuel rods in a reactor be replaced every few years? b. What happens to the fuel rods after they are taken out of the reactor?

6. Explain the difference between a fission reaction and a fusion reaction. Which type of reaction is used in nuclear power plants? (4pts)

7. Explain the difference between a n-type semiconductor and a p-type semiconductor. (4pts)

8. What is the equation E = mc2 used to calculate.? Identify what the symbols E, m and c represent. (4pts)