Introduction to Magnetic Effect of Electric Current
Physics is a vital subject of the Class 10 curriculum. The students should read all the chapters of this subject sincerely. In Class 10, the syllabus of physics contains introductory chapters of some vital concepts of physics. The magnetic effect of electric current is one of the most important chapters of the Class 10 Physics syllabus. This chapter is all about the magnetic effects created by the magnetic dipoles and electric charges. There are different causes of creating a magnetic field by the dipoles.
In this article, we are going to discuss the definition of the magnetic effect of electric current, the causes of the creation of a magnetic field, and the laws of magnetic fields.
Magnetic Effect of Electric Current Definition
Moving electric charges and magnetic dipoles create a force field (magnetic field), which is called the magnetic effect of electric current. This magnetic field exerts a force on the magnetic dipoles, and other moving charges near the force field. The magnetic field is a vector quantity and it has both magnitude value and direction. There can be different causes of the moving charges around the pole, which creates magnetic fields.
Magnetic Field Lines
When a magnetic field is created in an area, the magnetic dipoles create some particular force field lines. These lines are called magnetic field lines. Michael Faraday discovered the concept of magnetic field lines. Magnetic field lines show the direction of produced current and its strength. There are several laws about the characters and properties of magnetic field lines.
Direction of Field Lines
As the magnetic field is a vector quantity, magnetic field lines also have particular directions. The directions of magnetic field lines are different for inside and outside of the magnet. The magnetic field lines are directed from the north pole to the south pole outside the magnet. The direction of magnetic field lines inside the magnet is from the south pole to the north pole.
Strength of Magnetic Field Lines
Now, we are going to discuss the strength of magnetic field lines. Magnetic field strength is the intensity of the magnetic field. The magnetic field strength is proportional to the number of the magnetic field lines and their closeness. The closeness of the magnetic field lines is called the areal density. As the magnetic field lines don’t cross each other, the strength of the field is unique at any point of the magnetic field.
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Properties of Magnetic Field Lines
Magnetic field lines create the visualized format of the magnetic field. The magnetic field lines have some particular properties, which are mentioned below.
The magnetic field lines are proportional to the number of lines and their density.
The strength of magnetic field lines is proportional to the number of lines and their density.
Magnetic field lines cannot cross each other.
Magnetic field lines are continuous loops.
The direction of the field lines is indicated by arrows at any point (south pole to north pole inside the magnet and north pole to south pole outside the magnet).
The density of the field lines is high near the poles.
Laws About Magnetic Field
There are several laws depicting the characteristics, properties, and directions of the magnetic field. Biot Savart discovered the concept of the magnetic field and gave a law about the creation of the magnetic field. Hendrik A. Lorentz gave a law about calculating the force of a magnetic field. Michael Faraday discovered the concept of magnetic field lines.
Questions and Answers
1. What is a Magnetic Field?
Ans: Due to moving electric charges, a force field is created by the magnetic dipoles of a magnet. This force field area around a magnet is called a magnetic field.
2. What is Magnetic Intensity?
Ans: In a magnetic field, several magnetic field lines are located. These lines are at a particular distance. They don't cross each other. The density of the magnetic field lines in a magnetic field is called the strength of the magnetic field or magnetic intensity. In a particular area of the magnetic field, magnetic intensity is always unique.
3. What are the Properties of Magnetic Field Lines?
Ans: The major properties of magnetic field lines are-
Magnetic field lines are tangent to the respective magnetic field.
Magnetic field lines don't cross each other.
Magnetic field lines are continuous loops.
The direction of magnetic field lines is indicated by arrows.
The density of the magnetic field lines is high near the poles.
FAQs on Magnetic Effect of Electric Current
1. What is the magnetic effect of electric current?
The magnetic effect of electric current is the phenomenon where an electric current flowing through a conductor produces a magnetic field around it. This discovery by Hans Christian Oersted established that electricity and magnetism are linked, forming the basis of electromagnetism. Essentially, moving charges create a magnetic field.
2. What are the main properties of magnetic field lines?
Magnetic field lines are imaginary lines that visually represent a magnetic field. Their key properties are:
- They form continuous closed loops.
- Outside the magnet, their direction is from the North pole to the South pole.
- Inside the magnet, their direction is from the South pole to the North pole.
- The density of the lines indicates the field's strength; they are densest near the poles where the field is strongest.
- Two magnetic field lines can never cross or intersect each other.
3. Why can't two magnetic field lines ever intersect each other?
Two magnetic field lines cannot cross because the direction of the magnetic field at any given point is unique. If they were to intersect, it would imply that at the point of intersection, a compass needle would have to point in two different directions simultaneously. This is physically impossible, so field lines never cross.
4. What is Maxwell's Right-Hand Thumb Rule used for?
The Right-Hand Thumb Rule is a simple way to determine the direction of the magnetic field produced by a straight current-carrying conductor. It states: If you imagine holding the wire in your right hand with your thumb pointing in the direction of the electric current, the direction your fingers curl around the wire represents the direction of the magnetic field lines.
5. What is a solenoid, and how does it function like a bar magnet?
A solenoid is a long coil containing many close turns of insulated copper wire. When electric current flows through it, the solenoid generates a magnetic field pattern very similar to that of a bar magnet. One end of the solenoid acts as a North pole and the other as a South pole. The magnetic field inside the solenoid is strong and uniform, represented by parallel, straight field lines.
6. How can the strength of an electromagnet be increased?
An electromagnet is a solenoid with a soft iron core. Its strength can be increased in three main ways:
- By increasing the number of turns in the coil.
- By increasing the current flowing through the coil.
- By using a soft iron core inside the solenoid, which gets strongly magnetised and enhances the overall magnetic field.
7. Explain the working principle of an electric motor.
An electric motor operates on the principle that a current-carrying conductor placed in a magnetic field experiences a force. In a motor, a rectangular coil is placed in a magnetic field. When current flows through the coil, the opposing sides experience forces in opposite directions, causing the coil to rotate. This converts electrical energy into mechanical energy. The direction of force is given by Fleming's Left-Hand Rule.
8. What is the crucial role of the split-ring commutator in a DC motor?
The split-ring commutator in a DC motor acts as a device to reverse the direction of current. After every half rotation of the coil, the split rings change their contact with the brushes, reversing the current's direction in the coil. This reversal of current ensures that the torque continues to push the coil in the same direction, producing continuous rotation instead of just oscillating back and forth.
9. What is electromagnetic induction?
Electromagnetic induction (EMI) is the phenomenon of generating an induced electric current in a closed circuit or coil by changing the magnetic field around it. This can be done by moving a magnet relative to the coil or by changing the current in a nearby coil. This principle, discovered by Michael Faraday, is fundamental to the operation of electric generators.
10. How does an electric generator fundamentally differ from an electric motor?
The primary difference between an electric generator and an electric motor is their energy conversion and working principle:
- Function: A motor converts electrical energy into mechanical energy (rotation), while a generator converts mechanical energy into electrical energy (current).
- Principle: A motor uses the motor effect (force on a current in a magnetic field), governed by Fleming's Left-Hand Rule. A generator uses electromagnetic induction (current induced by motion in a magnetic field), governed by Fleming's Right-Hand Rule.
