11,400 years

eight days

10) How much time will be required for a sample of H-3 to lose 75% of its radioactivity? The half-life of tritium is 12.26 years. If you lose 75%, then 25% (0.25 as a decimal fraction) remains. 11) The half life of iodine-131 is 8.040 days.

The half-life is the time it takes for half of a given amount of an isotope to decay. For example, the half-life of carbon-14 is 5,730 years. Imagine that you start out with 100 grams of carbon-14. In 5,730 years, half of it decays.

Half-life, in radioactivity, the interval of time required for one-half of the atomic nuclei of a radioactive sample to decay (change spontaneously into other nuclear species by emitting particles and energy), or, equivalently, the time interval required for the number of disintegrations per second of a radioactive …

Hydrogen-7 ( about 23x10E-24) has the shortest half life.

Alpha particles

Now, let’s look at the different kinds of radiation. There are four major types of radiation: alpha, beta, neutrons, and electromagnetic waves such as gamma rays. They differ in mass, energy and how deeply they penetrate people and objects.

Alpha, beta and gamma radiations penetrate materials in different ways.

• Alpha radiation. Alpha radiation is the least penetrating. It can be stopped (or absorbed) by a sheet of paper or a human hand.
• Beta radiation. Beta radiation can penetrate air and paper.
• Gamma radiation. Gamma radiation is the most penetrating.

Gamma rays

In the case of alpha decay, a helium nucleus (two protons, and two neutrons) are emitted. This is the lowest energy radiation type, but it is none the less dangerous to human health. Here is an example of the alpha decay process.

Depending on their energy, they can be stopped by a thin piece of aluminum foil, or they can penetrate several inches of lead. In this experiment, we study the penetrating power of each type of radiation.

Radiation

• electromagnetic radiation, such as radio waves, microwaves, infrared, visible light, ultraviolet, x-rays, and gamma radiation (γ)
• particle radiation, such as alpha radiation (α), beta radiation (β), proton radiation and neutron radiation (particles of non-zero rest energy)

Alpha particle

alpha radiation

Civilian dose rates in peacetime range from 30 to 100 µGy per year. Fallout radiation decays relatively quickly with time. Most areas become fairly safe for travel and decontamination after three to five weeks.

It depends on the energy of the radiation and the size (or activity) of the source. Distance is a prime concern when dealing with gamma rays, because they can travel at the speed of light. Alpha particles can only travel a few inches and beta particles around 10 feet.

GEORGE LUCAS IS WRONG: You Can’t Survive A Nuclear Bomb By Hiding In A Fridge. “The odds of surviving that refrigerator — from a lot of scientists — are about 50-50,” Lucas said. But science has spoken, and it says something a little different.

within 10 miles

Gamma rays are electromagnetic radiation similar to X-rays, light, and radio waves. Gamma rays, depending on their energy, can pass right through the human body, but can be stopped by thick walls of concrete or lead. Neutrons are penetrating and can be stopped only by thick masses of concrete, water or paraffin.

Electromagnetic waves are produced by the motion of electrically charged particles. These waves are also called “electromagnetic radiation” because they radiate from the electrically charged particles. They travel through empty space as well as through air and other substances.

Clothes in a closet or drawer away from radioactive material are safe to wear. If you do not have clean clothes, take off your outer layer of clothing, shake or brush off your clothes taking care to cover your nose and mouth, and put your clothes back on.

Electromagnetic radiation travels in a straight line at the speed of light (3 x 108 m/s). Light waves, radio waves, microwaves, X-rays and Gamma rays are some examples of electromagnetic radiation. These waves differ in their wavelength as shown in the electromagnetic spectrum image above.