10th class physics lecture 3 alpha decay ,beta decay,gamma decay,ionizat...

NUCLEAR
TRANSMUTATIONS

Definition:

The spontaneous process in which a parent unstable nuclide changes into a more
stable daughter nuclide with the emission of radiations is called nuclear
transmutation

There are three types of decays occurs in
nature.

Alpha
(α)-decay:

alpha decay occurs when a heavier unstable 
nuclei with large number of protons split up in to lighter nuclei with
the emission of helium nuclei.

Beta
(β)-decay:

Beta decay occurs when unstable nuclei
(usually isotope) with extra neutrons changes in to another nuclei with the
emission of  electron.

Gamma
(ϒ)-decay
:

 Gamma decay occurs when excited nuclei,
deexcites with the emission of energy without any change in nuclei

Ionizing
Effect

Definition:

The
phenomenon by which radiations split matter into positive and negative ions is
called ionization. All three kinds of radiations i.e., alpha, beta and gamma
can ionize the matter.

Explanation:

 However, alpha particles have the
greatest

power of ionization as compared to beta particles and gamma rays.

It is due to large positive charge and
large mass of alpha particles.

Beta particles ionize a gas much less
than alpha particles.

The ionization power of gamma rays is
even

less than that of beta particles because gamma rays are neutral light
photons

Penetrating
Ability

Definition:

The
strength of radiations to penetrate a certain material is called penetrating
power.

The alpha particle has the shortest range
because of its strong interacting or ionizing power.

The beta radiation strongly interacts
with matter due to its charge and has a short range as compared to gamma
radiations

 The gamma rays can penetrate a
considerable

thickness of concrete. It is due to their large speed and neutral nature.

class 10 physics half life

HALF-LIFE
AND ITS MEASUREMENT

Definition:

The time during which half of the
unstable radioactive nuclei disintegrate is called the half-life of the sample
of radioactive element.

Explanation:

Process of radioactivity is
random and
the rate of
radioactive decay
is proportional to the number of unstable nuclei present.

In the process, a constant fraction of
large

number of unstable radioactive nuclei decays in a certain time.

 So
the life time of the unstable nuclei is unlimited and
is difficult to measure. We can get the idea about decay rate by the term
half-life.

Example:

Radium-226 has a half-life of 1620 years,
which means that half of a radium-226 sample will be converted to other
elements by the end of 1620 years. In the next 1620 years, half of the remaining
radium will
decay, leaving only one-fourth the original amount of radium, and so on

10th class physics natural radio activity,back ground radiation,cosmic r...

NATURAL
RADIOACTIVITY

Definition:

The spontaneous emission of radiation by
unstable nuclei is called natural radioactivity. And the elements which emit
such radiations are called radioactive elements.

Unstable
nuclei

Unstable nuclei are those nuclei whose
atomic number is greater than 82.Some isotopes are also unstable.

Discovery
of Radioactive elements:

In 1896, Becquerel accidentally
discovered that uranium salt crystals emit an invisible radiation that can
darken a photographic plate.

Henrey
Becquerel suggested that radioactivity was the result of the decay or
disintegration of unstable nuclei 

Marie Curie and her husband Pierre
discovered two new elements which emitted radiations. These were named polonium
and radium.

 This process of emission of radiations by some
elements was called natural radioactivity by Marie Curie.

BACKGROUND
RADIATIONS

Definition:

Radiations
present in atmosphere due to different

radioactive substances are called background radiations

Explanation:

Everywhere in rocks, soil, water, and air
of our

planet are traces of radioactive elements. This natural radiation is called the
background radiation.

It is as much part of our environment as
sunshine and rain.

 Fortunately, our bodies can tolerate it. Only
places where radiation is very high can be injurious to health.

Cosmic
radiation

Definition:

The Earth, and all living things on it
also receive radiation from outer space. This radiation is called cosmic
radiation

Explanation:

It primarily consists of protons,
electrons, alpha particles and larger nuclei.

The
cosmic radiation interacts with atoms in the atmosphere to create a shower of
secondary radiation, including X-rays, muons, protons, alpha particles,
electrons, and neutrons 

10th class physics properties of atom,atomic number,nucleon number,neutr...

Greek Philosopher Democritus in 585
BC

postulated that matter is built from small particles called atoms. The atom
means indivisible in Greek language

Atomic
number:

The atomic number Z
is
equal to the number of protons in the nucleus.

Neutron
number:

The neutron number N is equal to the number of neutrons in the
nucleus.

Atomic
mass number or Nucleon number:

The atomic mass number or nucleon number A is equal to the number of nucleons
(protons + neutrons) in the nucleus i.e., A= Z+N.

The
mass of neutron is nearly equal to that of proton. But proton is about 1836
times heavier than an electron. So the mass of an atom is nearly equal to the
sum of masses of protons and neutrons

Isotopes are atoms of an element which
have same number of protons but different number of neutrons in their nuclie.

        protium                deuterium                tritium

Three isotopes of Hydrogen Protium  ((_1^1)H ) 
contains one proton in the nucleus and one electron that revolves round
the nucleus.

Deuterium ((_1^2)H ) contains one proton, one neutron and
one electron.

Tritium ((_1^3)H ) contains one proton, two neutrons and
one electron.

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house safety alarm ,burglar alarm, application of NAND gate

House safety  Alarm or burglar alarm is the application of NAND gate. it ring the alarm when someone disrupt its inputs

NAND Gate ,NOR gate

NAND
Gate:

A NAND gate is formed by coupling a NOT
gate with the output terminal of the AND gate.

 The NOT gate inverts the output of the AND
gate. The output of the NAND gate  is
written as

X = (A.B) ̅.

It is read as X equals A AND B NOT.

Symbol:

 The NAND gate has been symbolically shown


In this figure, the NOT gate has been replaced with a small circle.

In the symbol of NAND gate, this small
circle attached at the output of AND gate shows NOT operation. 

NOR
Gate:

A NOR gate is formed by coupling a NOT
gate with the output terminal of the OR gate.

 The NOT gate inverts the output of the OR
gate. The output of the NOR gate  is
written as

X = (A+B) ̅.

It is read as X equals A OR B NOT.

Symbol:

 The NOR gate has been symbolically shown


In this figure, the NOT gate has been replaced with a small circle.

In
the symbol of NOR gate, this small circle attached at the output of OR gate
shows NOT operation. Table given is the