Radioactive decay occurs when the nucleus of an atom spontaneously disintegrates. Heavy atoms like uranium, thorium, radium, and polonium undergo this process, emitting alpha, beta, or gamma radiation. The rate of radioactive decay follows first-order kinetics, meaning the rate of decay is proportional to the amount of radioactive material. This allows scientists to define quantities like half-life, the time it takes for half of a radioactive sample to decay, and mean life, the average lifetime of radioactive atoms, which is equal to the half-life divided by the natural logarithm of two.
AS Level Physics' Radioactivity PresentationAkmal Cikmat
AS Level Physics' Radioactivity group presentation in class.
covers up the question on:
-Why certain nucleus is radioactive
-Radioactive process
-Half-life
-exponential decay curve
with a very lil' detail explanation for each subtopic.
Contents of this slide-share presentation:
Understanding decay concepts
Facts about Radioactive decay
Types of radioactive decay
Understanding Half-life concepts
Graphing and calculating Half-life
Using count rate to study and analyse radioactive decay
Radioactivity refers to the particles which are emitted from nuclei as a result of nuclear instability. Because the nucleus experiences the intense conflict between the two strongest forces in nature, it should not be surprising that there are many nuclear isotopes which are unstable and emit some kind of radiation.
Detection of Radioactivity
Characteristics of the Three Types of Emission
Nuclear Reactions
Half-Life
Uses of Radioactive Isotopes Including Safety Precautions
AS Level Physics' Radioactivity PresentationAkmal Cikmat
AS Level Physics' Radioactivity group presentation in class.
covers up the question on:
-Why certain nucleus is radioactive
-Radioactive process
-Half-life
-exponential decay curve
with a very lil' detail explanation for each subtopic.
Contents of this slide-share presentation:
Understanding decay concepts
Facts about Radioactive decay
Types of radioactive decay
Understanding Half-life concepts
Graphing and calculating Half-life
Using count rate to study and analyse radioactive decay
Radioactivity refers to the particles which are emitted from nuclei as a result of nuclear instability. Because the nucleus experiences the intense conflict between the two strongest forces in nature, it should not be surprising that there are many nuclear isotopes which are unstable and emit some kind of radiation.
Detection of Radioactivity
Characteristics of the Three Types of Emission
Nuclear Reactions
Half-Life
Uses of Radioactive Isotopes Including Safety Precautions
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
2. Early pioneers of
Radioactivity
Roentgen Becquerel
Rutherford
Marie curie
Pierre curie
Discover
Alpha Beta
particles and
Gamma
particles.
Discovery of
Radioactive
elements.
Discovered
Radium and
Polonium in
1900-1908
Henry
Becquerel
3. Radioactive Decay
• The phenomenon in which the nucleus of the heavy
atom undergoes spontaneous and uncontrollable
disintegration.
• heavy atoms include; uranium(U), thorium( th) ,
radium(Ra) and polonium(Po)
210
84po 4
2He + 206
82pb
• after disintigration Alpha , Beta , Gamma radiations
emiits.
5. Alpha radiations:
it is actually the nucleus of helium atom consisting of 2 protons and 2
neutreons,held tightly together.
the mass number decreases by 4
the atomic number decreases by 2
6. Beta Radiations:
a neutron changes into proton plus electron.the electron leaves the atom
with high energy as a beta particle.
the mass number remains the same.
the atomic number increase by 1.
131
53I 131
54Xe + 0
-1e
7. • Gama Radiation
a nucleus changes from a higher energy state to lower energy state throug
the emission of electromagnetic radiation called photons.
the number of protons and neutron in the nucleus does not change in this
process
8. Radioactivity Decay Law
• When a radioactive material undergoes α, β or γ-decay, the number of nuclei
undergoing the decay, per unit time, is proportional to the total number of
nuclei in the sample material.
•
•
• Where is a proportionality between radioactive decays per unit time and the
overall number of nuclei of radioactive compounds.
9. •
𝑑𝑁
𝑑 𝑡
= -λN
• By rearranging this
•
𝑑𝑁
𝑁
= -λdt
• Integration of both sides then result is;
• 𝑁0
𝑁
𝑑𝑁/𝑁 = −λ 𝑡0
𝑑𝑡
lnN-lnNo=- λ(t-to)
By putting t=0
𝑑𝑁
𝑁0
= - λt
N(t)-Noe - λt
10.
11. • SI unit of Activity is Becquerel
• 1 Becquerel =1 Bq =1 decay/s
• Curie =3.7*10 radioactive decay per second
12. Half - Life
T1/2
• the time required for half the amount of a radioactive
substance to decay.
• Every radionuclide has a characteristic half-life. Some half-
lives are only a millionth of a second, others are billions of
years.
13. Half life Derivation
N(t) = Noe-λt
t=T1/2 N=N0 /2
by putting the values N0/2 = N0 e-λt1/2
1/2=e
-λt1/2
2-1=e-λt1/2 Applying natural log on bothsides
ln2-1=ln e-λt1/2
-1ln2= -λt1/2 ln e
2.303*0.3010=λt1/2
0.693=λt1/2
t1/2=0.693/λ
14.
15. Mean life
• Mean life is the average lives of a radioactive substance.
• It is denoted by τ
τ=1/λ
Since, λ=0.693/T1/2
Hence,
τ= T1/2
0.693
