Physics Quiz 12

fission

process in which the nucleus of an atom splits into smaller parts resulting in two different nuclei with less mass

fusion

Combining of nuclei of light atoms such as hydrogen into heavier nuclei accompanied by the release of energy.

Which fundamental forces are involved in these two nuclear processes?

Strong Nuclear Force (Binds the nucleus together)

Electromagnetic Force (Positive protons repel)

What is directly produced by fission? (products)

2 daughter nuclei, free neutrons, & releases a very large amount of energy in the form of heat and light (gamma and x-rays)

What are some examples of where fission can be seen/used?

**Fission bombs** (use a simple design which takes small subcritical masses of material such as Uranium-235 or Plutonium-239 and joins them together into one supercritical mass.)

**Nuclear power** (is the use of nuclear reactors to release nuclear energy through fission which can then be used to generate electricity.)

What are some example of where fusion can be seen/used?

**Thermonuclear weapon (Hydrogen Bomb)** (is a nuclear weapon design that uses the energy from a primary nuclear fission reaction to compress and ignite a secondary)

**nuclear fusion reaction**

**Fusion power**

What is a chain reaction?

Most reactions produce two to three neutrons which are absorbed by other nuclei, causing them to fission, leading to a chain reaction

How does the amount (mass) of material determine if a chain reaction occurs?

the minimum amount (mass) of material needed to sustain a chain reaction.

subcritical mass

not enough mass - chain reaction cannot be sustained and dies out

super-critical mass

more than enough mass - chain reaction can build up explosively

What is the primary source of radioactive material currently used as a fuel source in nuclear reactions?

Uranium-235