FreeNotes
When a current-carrying coil is placed in a magnetic field, the interaction between the magnetic field and the current in the coil generates a torque. This torque tends to rotate the coil, and it’s the fundamental working principle behind electric motors. Why is Torque Applied on a Current-Carrying Coil? A current-carrying coil in a magnetic … Read more
The force applied on a current-carrying conductor in an external magnetic field arises due to the interaction between the magnetic field and the moving charged particles (electrons) in the conductor. When a current flows through a conductor, the electrons experience a force due to the magnetic field, which results in a net force on the … Read more
What is a Solenoid? A solenoid is a long coil of wire, typically wound in the shape of a cylinder, through which an electric current passes. It is designed to create a uniform magnetic field inside the coil and a more complex, weaker magnetic field outside it. Solenoids are commonly used in electromagnets, electric relays, … Read more
The magnetic field produced around a straight current-carrying conductor is a circular field that surrounds the wire. The direction of the magnetic field lines is determined by the current flowing through the conductor and can be described using Ampère’s Circuital Law. Magnetic Field Around a Straight Conductor: When an electric current flows through a conductor … Read more
Split rings (commutators) in a DC motor: They reverse the direction of current every half rotation to ensure continuous rotation in one direction. Slip rings in an AC motor: They do not reverse the current, allowing the coil to receive alternating current (AC) continuously, making the motor rotate smoothly in both directions. Related Questions: Two … Read more
According to Lenz’s Law, the induced current in the coil opposes the motion of the magnet. When the coil has more turns, the induced emf and current increase, producing a stronger opposing magnetic field. This results in a greater opposing force felt on your hand. Related Questions: Two parallel straight conductors carrying current in the … Read more
Step-up transmission is used for long distances because increasing voltage reduces current (as per P = VI). Since power loss (P = I²R) is directly proportional to current squared, reducing current minimizes heat loss in transmission lines, making electricity transmission more efficient over long distances. Related Questions: Two parallel straight conductors carrying current in the … Read more
The coils of a transformer are wound on an iron core to increase magnetic flux linkage between the primary and secondary coils. Iron is a good conductor of magnetic fields, so it helps concentrate and guide the magnetic field efficiently, reducing energy losses and increasing the efficiency of the transformer. Related Questions: Two parallel straight … Read more
A transformer works on the principle of electromagnetic induction, which requires a changing magnetic field to induce voltage in the secondary coil. When DC voltage is applied, the current remains constant, producing a steady magnetic field instead of a changing one. Since no electromagnetic induction occurs, no voltage is induced in the secondary coil, resulting … Read more
(a) The magnet is moving towards the ring According to Lenz’s Law, the ring will oppose the motion of the magnet by creating an induced current that produces a north pole on the side facing the approaching magnet. The induced current in the ring will be anticlockwise when viewed from above. (b) The magnet is … Read more