Class 12th – Electron theory of Electrification | Electric Charges and Fields | Tutorials Point
Summary
TLDRThis educational transcript delves into electron theories of electrification, explaining the atomic structure with a nucleus carrying a positive charge balanced by electrons' negative charge, resulting in a net charge of zero. It highlights the fundamental charge, or the charge of a single electron, as a key concept, measured in Coulombs. The script explores the exchange of electrons during processes like rubbing, which leads to objects becoming positively or negatively charged. It emphasizes that only electrons, due to their light mass, are responsible for electrification, not protons. The summary concludes with the impact of charging on an object's mass, noting that a negatively charged object gains mass from additional electrons, while a positively charged object loses mass as electrons depart.
Takeaways
- 🔬 Atoms consist of a positively charged nucleus and negatively charged electrons orbiting around it, resulting in a net charge of zero.
- 🚀 The fundamental charge, or the charge of a single electron, is a critical concept, denoted as 'e' and measured at 1.6 x 10^-19 Coulombs.
- ⚖️ The mass of an atom changes when it becomes charged; gaining electrons (negative charge) increases mass, while losing electrons (positive charge) decreases it.
- 🌐 The universe's net charge is zero due to the balance of equal numbers of protons and electrons in all atoms.
- 🔋 The process of electrification involves the transfer of electrons between objects, leading to one object gaining electrons (negative charge) and the other losing them (positive charge).
- ❌ Protons, being much heavier than electrons, do not typically move between atoms, making electrons solely responsible for electrification.
- 💡 The concept of charging by material transfer is essential; a body becomes negatively charged by gaining electrons and positively charged by losing them.
- 🔑 The electron's lightweight nature makes it the preferred particle for nature to move, influencing the charge state of objects.
- 📚 Understanding electron theory is crucial for grasping the basics of electricity and the behavior of different materials in electrical contexts.
- 📈 The script also hints at upcoming topics, such as the classification of materials into conductors, insulators, and semiconductors, and their electrical properties.
Q & A
What is the net charge of an atom?
-The net charge of an atom is zero because it consists of an equal number of electrons with negative charges and protons with positive charges in the nucleus.
What is the fundamental charge?
-The fundamental charge is the charge on one electron, which is the smallest unit of electric charge. It is 1.6 x 10^-19 Coulombs and is represented by the symbol 'e'.
Why are protons not exchanged during electrification processes?
-Protons are not exchanged during electrification processes because they are located in the nucleus of the atom and are much heavier than electrons. The mass of a proton is 1837 times that of an electron, making it less mobile and less likely to be transferred between atoms.
How does the mass of an object change when it becomes charged?
-When an object becomes negatively charged, its mass increases because electrons (which have mass) are added to it. Conversely, when an object becomes positively charged, its mass decreases as electrons are removed from it.
What is the role of electrons in the process of electrification?
-Electrons are solely responsible for electrification. They can be transferred between atoms, leading to an excess (negative charge) or deficiency (positive charge) of electrons in a material.
What happens during the process of rubbing two objects together?
-When two objects are rubbed together, there is a transfer of electrons from one object to another, resulting in one object becoming negatively charged (excess electrons) and the other becoming positively charged (deficiency of electrons).
Why are electrons considered lightweight in comparison to protons?
-Electrons are considered lightweight because their mass is significantly smaller than that of protons. This makes it easier for electrons to move between atoms, which is why they are involved in the process of electrification.
What is the significance of the number 1.6 x 10^-19 Coulombs in the context of the script?
-The number 1.6 x 10^-19 Coulombs represents the charge of a single electron, known as the fundamental charge. It is a standard measure used in physics to describe the magnitude of electric charge on subatomic particles.
How does the presence of an electron affect the charge of an atom?
-The presence of an electron contributes to the negative charge of an atom. If an atom gains an extra electron, it becomes negatively charged, and if it loses an electron, it becomes positively charged.
What are the two types of charges that can result from the transfer of electrons between atoms?
-The two types of charges that can result from the transfer of electrons between atoms are positive charge, which occurs when an atom loses electrons, and negative charge, which occurs when an atom gains excess electrons.
What is the relationship between the mass of an electron and the change in mass of a body when it becomes charged?
-The mass of an electron is 9.1 x 10^-31 kg. When a body becomes charged, its mass changes due to the addition or removal of electrons. If a body gains electrons, its mass increases, and if it loses electrons, its mass decreases.
Outlines
🔬 Electron Theories and Atomic Structure
This paragraph delves into electron theories of electrification, explaining that particles carry electric charges. It describes the atomic structure, with a nucleus carrying a positive charge and electrons orbiting around it with a negative charge. The net charge of an atom is zero due to an equal number of protons and electrons. The fundamental charge, or the charge on one electron, is identified as the smallest unit of charge, denoted as 'e' or -/+ 1.6 x 10^-19 Coulombs. The paragraph emphasizes that electrons, being lighter than protons, are more mobile and are responsible for the transfer of charge during processes like rubbing, which can result in an object becoming positively or negatively charged. The concept that the universe's net charge is zero is also introduced.
🌐 Electron Movement and Charge
The second paragraph focuses on the movement of electrons as the cause of electrical charge. It explains that while protons are heavier and less mobile, electrons are light and can be easily transferred between atoms, leading to either a positive or negative charge. The paragraph clarifies that protons rarely move between atoms due to their significant mass compared to electrons. It also discusses the concept that charging a body involves the transfer of electrons, which affects the mass of the body. Specifically, when a body becomes negatively charged, its mass increases due to the addition of electrons, and when it becomes positively charged, its mass decreases due to the loss of electrons. The mass of an electron is provided as 9.1 x 10^-31 kg, highlighting the significance of electron movement in the process of electrification.
📚 Charging and Mass Relationship
The final paragraph discusses the relationship between charging a body and the change in its mass. It reinforces the idea that charging involves the transfer of electrons, which in turn affects the mass of the object. The paragraph provides a clear explanation that a negatively charged body has gained mass due to the addition of electrons, while a positively charged body has lost mass due to the loss of electrons. The importance of understanding this relationship is emphasized, as it is fundamental to grasping the principles of electricity. The paragraph concludes with a note on the upcoming discussion about categorizing materials into conductors, insulators, and semiconductors, and how they behave in the context of electricity.
Mindmap
Keywords
💡Electron
💡Nucleus
💡Proton
💡Net Charge
💡Fundamental Charge
💡Electrification
💡Charge Carrier
💡Conductors, Insulators, and Semiconductors
💡Rubbing
💡Charge and Mass Relationship
Highlights
Atoms consist of a nucleus and electrons, with the nucleus carrying a positive charge and the electrons carrying a negative charge.
The net charge on an atom is zero due to an equal number of protons and electrons.
Electrons are the smallest in diameter, mass, and electric charge, representing the fundamental charge.
The charge on one electron is known as the basic charge, which is 1.6 x 10^-19 Coulombs.
The universe's net charge is zero because atoms and molecules are composed of equal numbers of protons and electrons.
Electrification occurs through the exchange of electrons, not protons, due to the latter's immobility in the nucleus.
The mass of an electron is very small, making it easier for nature to move electrons rather than protons during electrification.
The process of rubbing can cause a tug-of-war between electrons, leading to a transfer of charge and electrification.
An excess of electrons results in a negative charge, while a deficiency results in a positive charge.
The movement of electrons is responsible for the electrification process, not the movement of protons.
To make a particle positively charged, electrons must be removed from it.
The electron theory explains that charge is always carried by material, specifically electrons.
Charging a body results in a change in mass; a negatively charged body has increased mass due to the addition of electrons.
A positively charged body has decreased mass because electrons have left the body.
The mass of an electron is 9.1 x 10^-31 kg, which is extremely light.
Understanding the electron theory clarifies the fundamentals of electricity.
In the next class, the focus will shift to categorizing materials into conductors, insulators, and semiconductors and their behaviors.
Transcripts
to review study electron theories of
electrification we have studied that
some particles are carrying electric
charges and at the same time there are
researchers going on what happens inside
an atom so in an atom there is one
nucleus and there are electrons around
it it was formed when the nucleus was
separated from the atom we found it is
carrying positive charge so the net
charge on the atoms is zero net charge
on atom is zero and this nucleus is
positive if net charge is zero and
nucleus is positive that means all these
particles which we are separated are
carrying negative charge so all these
electrons are carrying negative charge
now when the study of electron was done
it was found that since this is zero
there are equal number of electrons
equal to the charges which are carrying
positive charge and we found that these
particles are known as protons so equal
number of electrons and protons are
present in an atom electrons are
carrying negative and this is carry
positive and this is what we write every
atom consists of equal number of
electrons in the orbits which have
negative charges and equal number of
protons in the nucleus which have
positive charges okay now we could not
get any particle smaller than neutral
and smaller than electron this is
smallest
in diameter smallest in mass and
smallest in electric charge so the net
charge or one electron is the minimum
charge and this makes the answer of one
a very important question which is
fundamental charge answer the charge on
one electron is f1
little charge okay fundamental charge
what is basic charge the charge on one
electron is known as basic charge and
how much it is our standard unit of
charge is Coulomb and which is a very
large unit but charge on one electron is
1.6 into 10 to the power minus 19
Coulomb because we need it frequently we
have given it a symbol small e now where
we can also write it negative and
positive that is minus e and plus C for
protons
okay then net charge on the atom
remember net charge on the atom is zero
because there are equal number of
protons and electrons if adam has got
charged zero then with the atoms
molecules are made zero charge with the
molecules any material is made zero
charge with the material our complete
universe is made so the net charge of
the complete universe is 0 because the
next charge effective is 0
ok now whenever there is a process of
rubbing or any other process we have the
exchange of electron how this exchange
happens and how this does not happen if
I take this there is a lot of space
between electrons like this and I put
another object on it so that object
electrons go like this now if I lift it
like this straight then there is no
problem but if I want to rub it rub it
means I want to move it like this then
there is a tug-of-war between the two
and what will happen either this will
break or this will break from this atom
and this is exactly what happens when I
put a chalk here when I put an ink here
and I rub it if I place it like this
lift nothing will happen but the moment
I rub it one or the other electron will
break and there will be excess electron
on one item and there will be loss of
electron in the other atom now if there
is a excess electron the excess of
electron that gives the negative charge
to that particular particle the loss of
electron creates a positive charge the
deficiency of electron makes positive
charge on that particle so if anybody
has got negative charge or particle
charge the responsibility is going on to
electron it is either excess of electron
or it is loss of electron but negative
or positive both are due to motion of
electron you can ask why why proton is
not exchanged if a proton goes to
another atom then that we get positively
charged but practically it does not
happen because proton is in the nucleus
and outside it is full of electrons
electrons number two electrons are light
their mass is very less and it is easy
to move them you all know the energy we
have half MV Square this M mass if
nature has to make negatively charged
particle there are two methods remove
this + or add one electron so nature
will choose adding the electrons because
electron is lightweight and it is very
easy to connect electrons electrons are
outside they are light therefore a very
small energy make them able to shift
from one atom to the other item
therefore it is only and
only electron which is responsible for
electrification and this thing I would
like to write here that it is only
electrons okay
it is only electron
which is responsible for electrification
and what I told you why not proton
the answer is proton is not mobile
due to its heavy mass
how heavier is the proton so proton is
1837 times heavier then electrons then
nature will always choose a lightweight
electron to be moved so it's only
electron which is responsible whether a
particle is getting positive charge
negative charge so remember when I asked
you how can we make this particle
positive you will not say that we will
shift certain positive charge to it what
will be your answer we will take out
some electron from it this will become
positively charged this is the method to
make any object as positively charged
particle okay so this is electron theory
all the seven points and you can
remember it seven number is not
important you should remember all the
points and if you remember all these
points then it will make all your
electricity very clear okay so after
this electron theory we will study what
are the effects one thing I would like
to add here before closing that will
there be any change in the mass when a
body is getting charged if this is carry
this is not charged now this is carrying
charge is there any change in its months
it appears that there is no change in
the mass but what does electron theory
says it says it will get negatively
charged only if some electrons have
entered on it this is a very very
important thing unless an electron comes
and sits on it this will not get
negatively charged we cannot give charge
without bringing a material with the
name electron so remember always charge
is always carried by material so if you
make it negatively charged one electron
has come from outside sit on it if you
get it positively charged one material
named electron has gone out of it now
this material is going out and you
material is coming in will there be any
change in the mass of course there will
be a change that means whenever we
charge a body there is certain a change
of mass okay no neutral neutral if we
give it negative charge what will
happens to its mass will it increase or
decrease yes the answer is it will
increase why negative means some excess
electron have gone on it and they will
increase its mass okay if a body gets
positive charge when we rub a glass it
become positively charged what happens
to its mass very simple answer how it
has become positively charged some
electrons have gone out if electrons
have gone out its mass has decreased so
remember negatively charged body
whenever it goes from zero charge to -
charge the mass increases and whenever
it become positively charged the mass
decreases and this we can count if we
know mass of a electron then we can
always count what is the change in the
mass okay so this is I should write it
charged mass relation so I will make a
note for you and you understand zero to
positive charge how it is made electron
leave the body
must decrease and if you want to know
mass of electron which you will see in
nucleus 9.1 10 to the power minus 31 kg
it is such a light so this is charging
oscillation okay so now in the next
class we will see how we divide the
different material around us into
different categories what we call
conductors insulators semiconductors and
how they behave
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