Welcome to the world of electromagnetism! In this comprehensive set of 10th class Physics notes, we will delve into Unit 15, where we explore the fascinating realm of electromagnetism. Electromagnetism is a fundamental branch of physics that investigates the relationship between electricity and magnetism, uncovering the profound connection between these two forces of nature. Throughout these notes, we will unravel the principles of electromagnetic induction, the behavior of magnetic fields, and the transformative power of electric currents. So, buckle up as we embark on a captivating journey into the electrifying world of Unit 15 Electromagnetism.
10th Physics Unit 15 Long Question Notes
10th Physics Unit 15 MCQ’s Long Question Notes
- 10th Class Pak Study Textbook
- 9th and 10th Class General Science Textbook
- Chapter No. 9 Notes 10th Chemistry
- Biology 10th Class Past Papers
- English Past Papers of 10th Class
10th Physics Unit 15 Numerical Notes
10th Physics Unit 15 Short Question Notes
What is Electromagnetism?
Answer: Electromagnetism is the study of magnetic effects of current.
How is magnetism produced by electric current in wires used in motors and electric meters?
Answer: Motors and electric meters are based on the effect of magnetism produced by the electric current in wires.
How does a current-carrying conductor produce a magnetic field around it?
Answer: When a current passes through a conductor, it produces a magnetic field around it.
What happens when you reverse the direction of the current in a conductor?
Answer: If the direction of the current is reversed, the magnetic field around the conductor also reverses its direction.
What is the Right Hand Grip Rule used for in electromagnetism?
Answer: The Right Hand Grip Rule is used to determine the direction of the magnetic field around a current-carrying conductor.
What is an electromagnet?
Answer: An electromagnet is a temporary magnet created when current flows through a coil.
How can the direction of the field produced by a coil be found?
Answer: The direction of the field produced by a coil can be found using the Right Hand Grip Rule.
What force does a current-carrying wire experience when placed in a magnetic field?
Answer: A current-carrying wire experiences a force when placed in a magnetic field, and the direction of the force depends on the direction of the current.
How can the force on a wire in a magnetic field be increased?
Answer: The force on a wire in a magnetic field can be increased by increasing the current in the wire, the strength of the magnetic field, or the length of the wire inside the magnetic field.
Why does Faraday’s description of the force on a current-carrying wire not completely specify the direction of force?
Answer: Because the force can be towards left or towards right.
What is Fleming’s left-hand rule used for?
Answer: Determining the direction of the force on a current-carrying wire in a magnetic field.
How do you determine the direction of the force using Fleming’s left-hand rule?
Answer: Stretch the thumb, forefinger, and middle finger of the left hand mutually perpendicular to each other. If the forefinger points in the direction of the magnetic field and the middle finger in the direction of the current, then the thumb would indicate the direction of the force acting on the conductor.
According to Fleming’s left-hand rule, what is the direction of the force on a current-carrying conductor placed in a magnetic field?
Answer: The force acting on the conductor is at right angles to both the directions of the current and magnetic field.
What is the working principle of electric motors?
Answer: Electric motors work based on the torque generated on a current-carrying coil (armature) placed in a magnetic field, causing it to rotate.
How can we make a coil rotate continuously in an electric motor?
Answer: By reversing the direction of the current just as the coil reaches its vertical position using a split ring commutator.
What factors can increase the total force acting on the armature in an electric motor?
Answer: Increasing the number of turns of the coil, increasing the current in the coil, increasing the strength of the magnetic field, and increasing the area of the coil.
How did Faraday discover electromagnetic induction?
Answer: He found that moving a wire through a magnetic field can induce an electric current in the wire.
What happens to the number of magnetic lines of force passing through a coil when it is moved closer to a magnet?
Answer: A large number of lines of force pass through the coil.
What is the basic principle of the production of electricity in electromagnetic induction?
Answer: Changing the number of magnetic lines of force through a coil by moving it in a magnetic field induces an electromotive force (e.m.f.) in the coil.
What is electromagnetic induction?
Answer: The process of generating an induced current in a circuit by changing the number of magnetic lines of force passing through it is called electromagnetic induction.
Describe Faraday’s experiment with the solenoid and magnet.
Answer: Faraday’s experiment involved moving a magnet into or out of a stationary solenoid. When the magnet was moved towards the solenoid, a current was induced in the solenoid, and the galvanometer needle deflected towards the right. When the magnet was pulled away from the solenoid, the induced current was in the opposite direction, and the galvanometer deflected towards the left.
What is Faraday’s law of electromagnetic induction?
Answer: Faraday’s law of electromagnetic induction states that an electromotive force (e.m.f.) is induced in a coil when there is a relative motion between the coil and a magnet.
According to Lenz’s law, what is the direction of an induced current in a circuit?
Answer: The direction of an induced current in a circuit is always such that it opposes the cause that produces it.
How does an AC generator work?
Answer: An AC generator works by rotating a coil in a magnetic field. As the coil turns, it cuts through the magnetic field lines, and this action induces an electromotive force (e.m.f.) in the coil, leading to the generation of an alternating current (AC) in the circuit. The strength and direction of the current change as the coil rotates through the magnetic field.
What is mutual induction?
Answer: Mutual induction is the phenomenon of producing an induced current in one coil due to a change of current in a neighboring coil.
How can mutual induction be demonstrated experimentally?
Answer: Place two coils, A and B, close to each other. Connect coil A to a battery and a switch, and connect a sensitive galvanometer to coil B. When the switch of coil A is closed, the galvanometer shows a momentary deflection, indicating the induction of current in coil B.
How does mutual induction affect the induced current in coil B when the switch in coil A is closed?
Answer: When the switch of coil A is closed, the changing current in coil A generates a changing magnetic field, leading to the induction of current in coil B, as per Faraday’s law. The induced current in coil B is temporary and gradually reduces to zero as the magnetic field stabilizes.
What happens to the galvanometer when the switch in coil A is opened?
Answer: When the switch in coil A is opened, the current flow through coil A stops, and its magnetic field collapses. This change in the magnetic field induces a current in coil B in the opposite direction compared to the previous case.
What is a transformer, and how does it work?
Answer: A transformer is a device based on mutual induction used to increase or decrease AC voltages. It has two coils, a primary and a secondary, wound around the same iron core. When an alternating current flows through the primary coil, it induces a changing magnetic field, which, in turn, induces an alternating electromotive force (emf) in the secondary coil.
What determines whether a transformer is step-up or step-down?
Answer: The ratio of the number of turns on the secondary coil (Ns) to the number of turns on the primary coil (Np) determines whether a transformer is step-up or step-down. If Ns is greater than Np, it is a step-up transformer; if Ns is smaller than Np, it is a step-down transformer.
How can transformers reduce power loss during high voltage transmission?
Answer: Transformers are used to step up the voltage during high voltage transmission. By increasing the voltage, the current through the transmission cable is reduced, minimizing the loss of energy in the form of heat due to cable resistance.
Why do transformers work only with AC?
Answer: Transformers work based on the principle of mutual induction, which requires a changing magnetic field. In AC systems, the current and, consequently, the magnetic field continuously change direction, making transformers suitable for AC applications.
What is a relay used for?
Answer: A relay is used to control a large current with the help of a small current.
Define a relay.
Answer: A relay is an electrical switch that opens and closes under the control of another electrical circuit.
How does a relay work?
Answer: The first circuit (input circuit) supplies current to the electromagnet, which magnetizes and attracts one end of the iron armature. The armature then closes the contacts (second switch) and allows current to flow in the second circuit. When the first switch is opened again, the current to the electromagnet stops, causing the second switch to open and stopping the flow of current in the second circuit.
What are some examples of the magnetic effect of an electric current?
Answer: Some examples of the magnetic effect of an electric current are a loudspeaker, circuit breaker, and door latches.