RADIOACTIVITY FORMULA SHEET FOR NEET PREPARATION

Introduction to Radioactivity:
Radioactivity is the spontaneous emission of radiation from the unstable atomic nucleus of an atom. It occurs in certain types of atoms that have an excess of either protons or neutrons, making them unstable.

Types of Radioactive Decay:
There are three main types of radioactive decay:
1. Alpha Decay: In alpha decay, an alpha particle is emitted from the nucleus, which consists of two protons and two neutrons.
2. Beta Decay: In beta decay, either a beta-plus particle (positron) or a beta-minus particle (electron) is emitted from the nucleus.
3. Gamma Decay: Gamma decay involves the emission of a gamma ray, which is a high-energy photon, from an excited nucleus.

Radioactive Decay Law:
The radioactive decay law describes the rate at which radioactive substances decay over time. It can be expressed using the following formula:
N(t) = N(0) * e^(-λt)
where N(t) is the number of radioactive atoms at time t, N(0) is the initial number of radioactive atoms, λ is the decay constant, and e is the base of the natural logarithm.

Half-Life:
The half-life of a radioactive substance is the time required for half of the radioactive atoms to decay. It can be calculated using the formula:
t(1/2) = (0.693 / λ)
where t(1/2) is the half-life and λ is the decay constant.

Radioactive Decay Series:
A radioactive decay series is a sequence of successive radioactive decays. Each decay in the series produces a different isotope until a stable isotope is reached. Some common decay series include the uranium series, thorium series, and actinium series.

Radioactive Decay Equations:
1. Alpha Decay Equation:
Parent Nucleus → Daughter Nucleus + Alpha Particle
Example:
U-238 → Th-234 + He-4

2. Beta-minus Decay Equation:
Parent Nucleus → Daughter Nucleus + Beta-minus Particle + Antineutrino
Example:
C-14 → N-14 + e- + ν

3. Beta-plus Decay Equation:
Parent Nucleus → Daughter Nucleus + Beta-plus Particle + Neutrino
Example:
O-15 → N-15 + e+ + ν

4. Gamma Decay Equation:
Excited Nucleus → Ground State Nucleus + Gamma Ray
Example:
Co-60* → Co-60 + γ

Conclusion:
Understanding the concepts and formulas related to radioactivity is crucial for NEET preparation. This formula sheet provides a concise summary of the key information needed to tackle questions related to radioactivity in the NEET exam. Make sure to practice solving numerical problems and familiarize yourself with different radioactive decay equations and their applications.