Electrically neutral point is a location at which the resultant electric force is zero. It means the charge kept at that point is experiencing equal and opposite force due to the other two charges kept in that line. To find the neutral point, we can equate the two forces and when the two charges are of similar nature, we can get null point between the charges existing in one line and beyond them, we are not going to find the neutral point. At a location beyond the neutral point, the force acting on the third charge are in the same direction and hence there will not be any neutral point. It is explained in the following video lesson and the location of neutral point is also derived.
Showing posts with label Charge. Show all posts
Showing posts with label Charge. Show all posts
Electric force of attraction or repulsion exists between every two charges and it follows Coulomb's inverse square law. According to the law, the force between two charges is directly proportional to the product of charges and is inversely proportional to the square of the distance of separation.
Gravitational and electric forces are fundamental in nature. Gravitational force is due to mass of the particle and it exits between every two masses where as electric force exits between the the particles or bodies having only excess charges. Both of them obeys inverse square law but gravitational force is independent of medium but electric force depends on the medium between charges.
Gravitational force is the weakest of fundamental forces but electric force is much stronger than that. Gravitational force is further always attractive force but electric force is either attractive or repulsive. Further classification is explained in the video lesson below.
Electric Potential Problems with Solutions
Electrostatic Potential Energy Expression
Working of Capacitor and Dielectric effect on Capacity
Capacitors in Series and parallel with Problems and Solutions
Energy Stored in Capacitor and Effect of Dielectric on it
Properties of Electric Charges Video Lesson
Neutral Point and Equilibrium of Electric charge in a line Video Lesson
Electric charge is the property of a particle of certain mass due to which it can either attract the opposite charge or repel the similar charge.Charges are classified as positive and negative and many bodies around are neutral which means they have equal and opposite charges.
When one body with excess charges is rubbed with the other, there is transfer of electrons from one body to other. The body lost electrons will have excess positive charges and the body that gained electrons will have excess electrons. Thus the body that gained electrons is negatively charged and the body that lost electrons is positively charged.
Thus body that is positively charged losses a small portion of mass due to loss of electrons and the body that gained electrons is not only negatively charged but its mass is also slightly increases.
Electromagnetism is a branch of physics that deals with the magnetic field developed around the current carrying conductor or moving charge. To find the magnitude of the magnetic field induction, we can use Biot-Servert's law and ampere's law. We can define the fundamental unit to measure the current ampere basing on this definitions. We can also measure force between two straight conductors. As mentioned in the posts in the relevant topics, we can find magnetic induction for different kind of current carrying conductors using these rules.
If a current carrying conductor is placed under the magnetic field, it experience two magnetic fields and because of them, there is torque experienced by the current carrying conductor and we can design moving coil galvanometer basing on this concept. It can be even converted into Ammeter and voltmeter. All these are discussed in detail in the following posts.
Related Posts
Other complete lessons in this blog are mentioned here for the reference.
Mechanical Properties of Matter
Heat and Thermodynamics
Waves and Oscillations
Ray Optics
Mechanical Property of Solids Elasticity Complete Lesson
Waves and Oscillations
Ray Optics
Friction Complete Video Lessons
Center of Mass Complete Video Lessons
Rotational Dynamics complete Video Lesson
Gravitation Complete Lesson
Current Electricity Complete Lesson
Let us consider two infinitely straight long conductors carrying current in the same direction.We can measure the force between the two conductors as shown
below. We need to use the formula that we have derived the formula for the
magnetic field at a given point using the Ampere’s law.
Basing on the magnetic field, we have derived for the force
experienced by the point at a distance using the formula that was also derived.
The second conductor also carrying current and experience due
to the other conductor similar to the first conductor. These forces are mutual
and we can derive as shown below.
Definition of ampere
We can define the ampere basing on the derivation as
derived earlier. If two infinitely long straight conductors carrying a
certain current separated by unit distance experience a force of repulsion
per unit length, the current passing
through each conductor is one ampere.
This is treated like a fundamental unit in the SI system and is defined As shown below.
Related Posts
We can find the magnetic field around a wire on the axial
line of charge using the Biot-Servert’s law. We are not adding the derivation
here and the expression is as shown in the figure.
Let us consider a point on the axial line at a particular
distance and let us assume that we know the radius at any given point.
The expression for the magnetic field at any point can be expressed
as shown in the diagram. If we are measuring it at the center of the circle, we
need to equate the value to zero.
We can also find out the force acting basing on
Biot-Servert’s law. We can find the magnetic field at any given point using
this rule. We know that the magnetic induction is defined as the force
experienced by a unit north pole when placed in a magnetic field.
Thus we can measure the force as the product of the pole
strength and magnetic induction. As the field is small component, the force is
also small component. To get the total force acting on the point, we need to
integrate the given equation and we can get the total force as shown in the
diagram below.
This force will be maximum when the point is perpendicular to
the current carrying conductor. If the
angle is zero or 180 degree, the force will become zero as shown below.
To find the
direction of the force experienced
by the current carrying conductor
using Fleming Left hand rule. As per the law, if fore finger
indicate the direction of the magnetic
field and central finger indicates
the direction of the current then the thumb indicates the direction of the thrust or
force experienced by the current carrying conductor.
We can also measure
the force acting on a charge simply by
defining the current as the rate of
charge. We can define as the cross product of velocity of the charge and the
magnetic field and the product is multiplied
with the charge.
We can define the
unit of magnetic induction tesla basing on the above derivation. The magnetic field induction is the force experienced by
the conductor when a unit charge passing through a conductor with unit velocity at right angle.
Related Posts
We can also find out the magnetic field induction at any
point due to a charge using the Ampere’s law.According to this rule the line integral of magnetic
induction around a closed curve is permittivity of free space times the current
in that closed loop.
Problem and solution
Let us consider a current carrying conductor in circular
shape and we are interested in the magnetic field at the center of the coil. We
can use the formula that we have derived to do that and we shall assume that
the distance of the particle on the perpendicular axis is zero. It is because
we are measuring it at the center of the coil. The problem is solved as shown
below.
When we measure the line integral, we get the length of the
wire around which we are measuring the magnetic field. We also need to measure
the magnetic field only due to currents inside the closed loop. We need not
worry about the currents outside as they do not produce any impact. We are
measuring only due to the portion of currents that are in the closed loop.
The currents with in the loop which are coming into the loop
are treated as positive and currents leaving the closed circuit shall be
treated as negative.
Basing on this Ampere’s law, we can find the magnetic field
around a closed straight current carrying conductor of infinite length as shown
below.
Let us assume a conductor carrying a current “I” as shown in
the figure. We would like to measure the magnetic field around it at a distance
“r” from it. We can consider the line
integral around it as the circular path of the given radius and when we line
integrate it; we get the length of that closed path. It is nothing but the
circumference of the circle.
It is the dot product of the magnetic field and the component
of the length due to which we need to measure the field as per the Amper’s law.
Any way the field and the portion of the length are in the same direction and
the angle is treated as zero.
In the place of that line integral of the component of the
length, we need to write the circumference as shown and we can find the
magnetic field as shown below.
Related Posts
Current electricity is a branch of physics that deals with the charges in motion and its applications. Current flows through the conductors and while it is happening some opposition is there called resistance. In this lesson we have analyzed on whom this resistance is depending on and how can we measure it. To measure the nature of resistance and its dependence, a physical quantity called specific resistance is also defined. It depends on the nature but not on the physical dimensions of a body.
To know the dependence of the current on potential difference in simple cases, Ohm's law is defined and to study the complex cases, we have Kirchhoff's laws. To know about the impact of resistance, we have Wheatstone bridge and its application Meter bridge. We also deal here about potentiometer and it is useful to compare the EMF of different cells and to find the internal resistance of a battery. Detailed lessons were made about each of the above topics and they are listed here for the reference.
Resistance and Specific Resistance
EMF and Internal Resistance of a Cell
Kirchhoff's Laws and Explanation
Kirchhoff's Law Problems and Solutions
Wheatstone bridge and Meter Bridge
Potentioemeter Comparison of EMF's and Determination of Internal Resistance
Resistors in Series and Parallel Problems and Solutions
Other complete lessons in this blog are mentioned here for the reference.
Mechanical Properties of Matter
Heat and Thermodynamics
Waves and Oscillations
Ray Optics
Mechanical Property of Solids Elasticity Complete Lesson
Waves and Oscillations
Ray Optics
Friction Complete Video Lessons
Center of Mass Complete Video Lessons
Rotational Dynamics complete Video Lesson
Gravitation Complete Lesson
Electrostatics is a branch of physics that deals with charges in the state of rest and its applications. Here in this chapter we are going to deal about charge, electric field, electric force between charges,electric intensity,electric potential,potential difference, electric potential energy,capacitor, capacity, effect of dielectric on the capacity and energy stored in capacitor etc. Detailed lessons are made about each of the topic and they are listed here below for the reference.
Electric Charge and Electric Force
Working of Capacitor and Dielectric effect on Capacity
Capacitors in Series and parallel with Problems and Solutions
Energy Stored in Capacitor and Effect of Dielectric on it
Here are the further list of topics with complete lessons in this website.
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