<–2/”>a >Electrostatic
The basic principle of Electrostatics is based on the fact the electric charges attract or repel other charges depending on their relative signs and the law of force is given by Coulomb‘s law.
Coulomb’s law states that: The magnitude of the electrostatic force of interaction between two point charges is directly proportional to the scalar multiplication of the magnitudes of charges and inversely proportional to the square of the distance between them. The force is along the straight line joining them.
The electric field E at a point is defined as the electric force F experienced by a positive test charge q placed at that point divided by the magnitude of the test charge.
Properties of Electric Lines of Force or Field Lines
- The electric lines of force are imaginary lines.
- A unit positive charge placed in the electric field tends to follow a path along the field line if it is free to do so.
- The electric lines of force emanate from a positive charge and terminate on a negative charge.
- The tangent to an electric field line at any point gives the direction of the electric field at that point.
- Two electric lines of force can never cross each other. If they do, then at the point of intersection, there will be two tangents. It means there are two values of the electric field at that point, which is not possible. Further, electric field being a vector quantity, there can be only one resultant field at the given point, represented by one tangent at the given point for the given line of force.
- Electric lines of force are closer (crowded) where the electric field is stronger and the lines spread out where the electric field is weaker.
- Electric lines of force are perpendicular to the surface of a positively or negatively charged body.
- Electric lines of force contract lengthwise to represent attraction between two unlike charges.
- Electric lines of force exert lateral (sideways) pressure to represent repulsion between two like charges.
10.The number of lines per unit cross – sectional area perpendicular to the field lines (i.e. density of lines of force) is directly proportional to the magnitude of the intensity of electric field in that region.
- Electric lines of force do not pass through a conductor. Hence, the interior of the conductor is free from the influence of the electric field.
- Electric lines of force can pass through an insulator.
Gauss’s Law states that The total of the electric flux out of a closed surface is equal to the charge enclosed divided by the permittivity.
Electric field from uniformly charged thin spherical shell:
outside the shell with magnitudeinside the shellwhere:
Q is total charge of the shell
R is radius of the shellis position vector of point P where the electric field is defined
Electric field from uniformly charged solid sphere:outside the sphere with magnitudeinside the sphere with magnitude
Electric field from uniformly charged thin line:
with magnitude where:is linear charge density of the line with length L charged by charge Q
is radius-vector drawn perpendicular to axis of the line from the axis to the point where the electric field is defined
Electric field from uniformly charged thin cylindrical shell:
outside the shell with magnitude
inside the shell
Electric field from uniformly charged solid cylinder:
outside the cylinder with magnitude
inside the cylinder with magnitude
where:
is linear charge density of the cylinder with length L charged by charge Q
R is radius of cylinder
is radius-vector normal to axis of the line drawn from the axis to the point where the electric field is defined,
Electrostatics is the branch of physics that deals with the electric charges at rest. It is a very important field of physics, as it is the basis for many other fields, such as electricity, Magnetism, and electromagnetism.
Electric charge is a fundamental property of matter. It is carried by protons and electrons, and it can be positive or negative. Like charges repel each other, and unlike charges attract each other.
The electric field is a region of space around an electric charge where a force is exerted on other charges. The electric field is strongest near the charge and weakens with distance.
The electric potential is a measure of the electric potential energy per unit charge. The electric potential energy is the energy that a charge has due to its position in an electric field.
The electric potential difference is the difference in electric potential between two points. The electric potential difference is also called the voltage.
The electric current is the flow of electric charge. The electric current is measured in amperes.
The electric resistance is the opposition to the flow of electric current. The electric resistance is measured in ohms.
The electric conductance is the ability of a material to conduct electricity. The electric conductance is measured in siemens.
The electric resistivity is the resistance of a material per unit length and cross-sectional area. The electric resistivity is measured in ohms per meter.
The electric conductivity is the inverse of the electric resistivity. The electric conductivity is measured in siemens per meter.
An electric circuit is a closed path through which an electric current can flow.
An electric potential difference across a resistor causes a current to flow through the resistor. The current is proportional to the electric potential difference and inversely proportional to the resistance.
An electric potential difference across a capacitor causes an electric charge to accumulate on the capacitor plates. The electric charge is proportional to the electric potential difference and inversely proportional to the capacitance.
An electric potential difference across an inductor causes an electric current to flow through the inductor. The current is proportional to the electric potential difference and inversely proportional to the inductance.
Electric power is the rate at which electric energy is transferred. Electric power is measured in watts.
Electric energy is the energy that is stored in an electric field or that is used to move an electric charge. Electric energy is measured in joules.
Electric work is the work that is done by an electric force. Electric work is measured in joules.
Electric circuit analysis is the study of how electric circuits work. Electric circuit analysis is used to design and analyze electric circuits.
Electric Network analysis is the study of how electric networks work. Electric network analysis is used to design and analyze electric networks.
Electric field theory is the study of electric fields. Electric field theory is used to explain the behavior of electric charges and electric currents.
Electrostatics is a very important field of physics. It is the basis for many other fields, such as electricity, magnetism, and electromagnetism. Electrostatics is used in many everyday devices, such as batteries, capacitors, and motors.
What is electricity?
Electricity is a form of energy that is produced by the movement of electrons. Electrons are tiny particles that are found in atoms. When electrons move, they create an electric current. This current can be used to power devices, such as lights and computers.
What is magnetism?
Magnetism is a force that attracts or repels certain materials. Materials that are attracted to magnets are called ferromagnetic materials. These materials include iron, nickel, and cobalt. Materials that are not attracted to magnets are called non-ferromagnetic materials. These materials include wood, plastic, and glass.
What is electromagnetism?
Electromagnetism is a force that is created by the interaction of Electricity and Magnetism. Electromagnets are created when an electric current is passed through a coil of wire. This current creates a Magnetic Field around the coil. Electromagnets can be used to power motors, generators, and other devices.
What is static electricity?
Static electricity is a buildup of electric charge on an object. This charge can be caused by friction, rubbing, or contact with another object. When an object has a static charge, it can attract or repel other objects. Static electricity can also cause sparks and shocks.
What is lightning?
Lightning is a discharge of electricity that occurs between clouds or between a cloud and the ground. Lightning is caused by the buildup of static electricity in clouds. When the static charge becomes too strong, it discharges in a flash of lightning. Lightning can be very dangerous and can cause fires, injuries, and death.
What is a capacitor?
A capacitor is a device that stores electric charge. Capacitors are made up of two conductive plates that are separated by an insulator. When a voltage is applied to the capacitor, the charge builds up on the plates. The amount of charge that a capacitor can store depends on its capacitance.
What is an inductor?
An inductor is a device that stores energy in a magnetic field. Inductors are made up of a coil of wire. When a current flows through the coil, it creates a magnetic field. The magnetic field stores energy. The amount of energy that an inductor can store depends on its inductance.
What is a resistor?
A resistor is a device that resists the flow of electric current. Resistors are made up of a material that has a high resistance to the flow of electrons. The resistance of a resistor is measured in ohms.
What is a diode?
A diode is a device that allows current to flow in one direction only. Diodes are made up of a semiconductor material. When a voltage is applied to a diode, current flows through the diode in the forward direction. However, when a voltage is applied to the diode in the reverse direction, no current flows.
What is a transistor?
A transistor is a device that can be used to amplify or switch electronic signals. Transistors are made up of semiconductor materials. Transistors are used in a wide variety of electronic devices, such as computers, radios, and televisions.
What is a integrated circuit?
An integrated circuit is a small electronic device that contains many transistors and other electronic components. Integrated circuits are made up of a thin layer of semiconductor material. Integrated circuits are used in a wide variety of electronic devices, such as computers, cell phones, and cars.
What is a microprocessor?
A microprocessor is a small computer that is used to control electronic devices. Microprocessors are made up of millions of transistors. Microprocessors are used in a wide variety of electronic devices, such as computers, cell phones, and cars.
What is a computer?
A computer is an electronic device that can be programmed to carry out sequences of arithmetic or logical operations automatically. Computers are used for a wide variety of tasks, such as word processing, data storage, and Communication.
What is the Internet?
The internet is a global system of interconnected computer networks that use the standard Internet protocol suite (TCP/IP) to serve billions of users worldwide. It is a network of networks that consists of millions of private, public, academic, business, and government networks, of local to global scope, that are linked by a broad array of electronic, wireless, and optical networking technologies. The Internet carries an extensive range of information Resources and Services, such as the inter-linked hypertext documents and applications of the World Wide Web (WWW), electronic mail, telephony, and file sharing.
Sure, here are some MCQs without mentioning the topic Electrostatics:
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Two objects are attracted to each other. What can you conclude about the charges on the objects?
(A) The objects have the same charge.
(B) The objects have opposite charges.
(C) The objects have no charge. -
A charged object is brought near an uncharged object. What will happen to the uncharged object?
(A) It will be attracted to the charged object.
(B) It will be repelled by the charged object.
(C) It will not be affected by the charged object. -
A charged object is placed in a region of space with a uniform electric field. What will happen to the object?
(A) It will move in the direction of the electric field.
(B) It will move in the opposite direction of the electric field.
(C) It will not move. -
Two charged objects are placed near each other. The force between the objects is attractive. What can you conclude about the charges on the objects?
(A) The objects have the same charge.
(B) The objects have opposite charges.
(C) The objects have no charge. -
A charged object is placed in a region of space with a non-uniform electric field. What will happen to the object?
(A) It will move in the direction of the electric field.
(B) It will move in the opposite direction of the electric field.
(C) It will move in a curved path. -
Two charged objects are placed near each other. The force between the objects is repulsive. What can you conclude about the charges on the objects?
(A) The objects have the same charge.
(B) The objects have opposite charges.
(C) The objects have no charge. -
A charged object is placed in a region of space with a uniform electric field. The object experiences a force of 1 N. What is the electric field strength in this region of space?
(A) 1 N/C
(B) 10 N/C
(C) 100 N/C -
A charged object is placed in a region of space with a non-uniform electric field. The object experiences a force of 1 N. What is the electric field strength in this region of space?
(A) Cannot be determined without knowing the charge on the object.
(B) 1 N/C
(C) 10 N/C -
A charged object is placed in a region of space with a uniform electric field. The object experiences a force of 1 N. The charge on the object is 1 C. What is the electric field strength in this region of space?
(A) 1 N/C
(B) 10 N/C
(C) 100 N/C -
A charged object is placed in a region of space with a non-uniform electric field. The object experiences a force of 1 N. The charge on the object is 1 C. What is the electric field strength in this region of space?
(A) Cannot be determined without knowing the mass of the object.
(B) 1 N/C
(C) 10 N/C