Inaugurated by IN-SPACe
ISRO Registered Space Tutor
S7-SA4-0592
What is the Beta-Plus Decay?
Grade Level:
Class 12
AI/ML, Physics, Biotechnology, FinTech, EVs, Space Technology, Climate Science, Blockchain, Medicine, Engineering, Law, Economics
Definition
What is it?
Beta-plus decay is a type of radioactive decay where a proton inside an unstable atomic nucleus changes into a neutron, emitting a positron (a positively charged electron) and a neutrino. This process helps the nucleus become more stable by reducing its number of protons and increasing its neutrons.
Simple Example
Quick Example
Imagine you have a cricket team with too many batsmen and not enough bowlers. To make the team balanced and stronger, one batsman decides to become a bowler. In beta-plus decay, a 'too many protons' nucleus changes a proton into a neutron, making it more stable, like balancing the cricket team.
Worked Example
Step-by-Step
Let's look at the decay of Carbon-11 (¹¹C), which undergoes beta-plus decay.
1. **Starting Nucleus:** We begin with Carbon-11. Its atomic number (Z) is 6 (meaning 6 protons) and its mass number (A) is 11.
2. **Proton Changes:** One proton in the Carbon-11 nucleus transforms into a neutron. This means the atomic number decreases by 1.
3. **Positron Emission:** A positron (e⁺ or ⁰₁β) is emitted, carrying away the positive charge that the proton had.
4. **Neutrino Emission:** An electron neutrino (ν) is also emitted to conserve energy and momentum.
5. **New Nucleus Formation:** Since the atomic number decreased by 1, the element changes from Carbon (Z=6) to Boron (Z=5). The mass number (A) remains the same because a proton changed into a neutron, so the total number of nucleons (protons + neutrons) doesn't change.
6. **Final Equation:** The decay can be written as: ¹¹₆C → ¹¹₅B + ⁰₁e + ν
7. **Answer:** Carbon-11 decays into Boron-11, a positron, and a neutrino.
Why It Matters
Beta-plus decay is super important in medicine, especially for imaging techniques like PET scans used to detect diseases in hospitals. It's also used in research to understand how different elements form and behave, helping scientists in fields like biotechnology and materials science to create new things.
Common Mistakes
MISTAKE: Thinking beta-plus decay involves emitting a regular electron. | CORRECTION: Beta-plus decay emits a POSITRON, which is like an electron but with a positive charge.
MISTAKE: Believing the mass number (A) changes in beta-plus decay. | CORRECTION: The mass number (A) remains the same because a proton just converts into a neutron; the total number of nucleons (protons + neutrons) stays constant.
MISTAKE: Confusing beta-plus decay with beta-minus decay. | CORRECTION: Beta-plus decay changes a proton to a neutron and emits a positron, while beta-minus decay changes a neutron to a proton and emits an electron.
Practice Questions
Try It Yourself
QUESTION: When an atom undergoes beta-plus decay, what happens to its atomic number (Z)? | ANSWER: The atomic number (Z) decreases by 1.
QUESTION: Write the nuclear equation for the beta-plus decay of Oxygen-15 (¹⁵₈O). | ANSWER: ¹⁵₈O → ¹⁵₇N + ⁰₁e + ν
QUESTION: A radioactive isotope with 10 protons and 10 neutrons undergoes beta-plus decay. What will be the atomic number and mass number of the new nucleus formed? | ANSWER: The new nucleus will have 9 protons (atomic number 9) and 11 neutrons. The mass number will remain 20 (9+11).
MCQ
Quick Quiz
Which particle is emitted during beta-plus decay?
Electron
Neutron
Positron
Alpha particle
The Correct Answer Is:
C
Beta-plus decay involves a proton changing into a neutron and emitting a positron. An electron is emitted in beta-minus decay, and an alpha particle is a helium nucleus.
Real World Connection
In the Real World
In Indian hospitals, doctors use PET (Positron Emission Tomography) scans to check for diseases like cancer or heart problems. These scans use special radioactive tracers that undergo beta-plus decay, emitting positrons. When these positrons meet electrons in the body, they produce gamma rays that are detected by the scanner, creating detailed images of organs and tissues.
Key Vocabulary
Key Terms
RADIOACTIVE DECAY: The process where an unstable atomic nucleus loses energy by emitting radiation | PROTON: A positively charged particle found in the nucleus of an atom | NEUTRON: A neutral particle found in the nucleus of an atom | POSITRON: A particle identical to an electron but with a positive charge | ATOMIC NUMBER (Z): The number of protons in an atom's nucleus
What's Next
What to Learn Next
Great job understanding beta-plus decay! Next, you should learn about 'Beta-Minus Decay' and 'Alpha Decay'. Comparing these different types of radioactive decay will help you understand how unstable atoms transform to become stable, which is a core concept in nuclear physics.
