Reading Time: 2 minutesAlpha Radiation (
Beta Radiation (
Gamma Radiation (
Half-Life (
Radioactivity: Exploring Alpha, Beta, and Gamma Radiation
What Is Radioactivity?
Radioactivity is the spontaneous emission of radiation by unstable atomic nuclei, transforming into more stable configurations.
Types of Radiation
Alpha Radiation (
)
)- Consists of 2 protons and 2 neutrons.
- Low penetration power; stopped by paper or skin.
Beta Radiation (
)
)- Consists of high-energy electrons (
) or positrons (
). - Moderate penetration power; stopped by aluminum.
) or positrons (
).Gamma Radiation (
)
)- High-energy electromagnetic waves.
- High penetration power; stopped by lead or thick concrete.
Half-Life (
)
)The time required for half the radioactive nuclei in a sample to decay:
![\[ N = N_0 \left(\frac{1}{2}\right)^{t/T_{1/2}} \]](https://on22.com/wp-content/ql-cache/quicklatex.com-4330f4d64e256b7015a799d1fe012168_l3.png "Rendered by QuickLaTeX.com")
Where:
: Initial quantity of nuclei.
: Remaining nuclei after time 
.
: Initial quantity of nuclei.
: Remaining nuclei after time 
.Applications of Radioactivity
Medicine
Radioisotopes are used in cancer treatment and imaging (e.g., PET scans).
Archaeology
Radiocarbon dating determines the age of ancient artifacts.
Energy Production
Nuclear reactors harness radioactive decay for electricity.
Example Problem
A radioactive sample has a half-life of 
. If the initial mass is 
, how much remains after 
?
- Formula:
- Substitute Values:
![\[ N = 100 \cdot \left(\frac{1}{2}\right)^{15/5} = 100 \cdot \left(\frac{1}{2}\right)^3 = 12.5 \, \text{g} \]](https://on22.com/wp-content/ql-cache/quicklatex.com-115c9fa31d2d0643429a18744f6e3ff6_l3.png "Rendered by QuickLaTeX.com")
Common Mistakes in Radioactivity Calculations
- Forgetting to use consistent units for time and half-life.
- Mixing up activity and decay rate.
- Ignoring the shielding required for different radiation types.
Practice Questions
- A radioactive isotope has a half-life of
. If 
is present initially, calculate how much remains after 
. - Explain the differences between alpha, beta, and gamma radiation.
- Describe one application of radioactive isotopes in medicine.
. If 
is present initially, calculate how much remains after 
.
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