Self induction is the phenomenon where a changing current in a coil induces an electromotive force (emf) in the same coil itself.
What is the unit of self inductance?
The unit of self inductance is the Henry (H).
What is the self-induced emf formula?
The self-induced emf (E) can be calculated using E = -L(dI/dt), where L is the self inductance, and dI/dt is the rate of change of current.
Explain Lenz's Law in the context of self induction.
Lenz's law states that the direction of the self-induced emf opposes the change in current that produced it.
What factors affect self inductance?
Self inductance is influenced by the number of turns in the coil, the coil's area, the permeability of the core material, and the length of the coil.
How does increasing the number of coil turns affect inductance?
Increasing the number of turns in a coil increases its inductance because it increases the amount of magnetic flux for a given current.
What is the physical significance of self inductance?
Self inductance represents a circuit's ability to oppose changes in current due to its own magnetic field.
Describe an application of self induction in technology.
One common application is in transformers, where self inductance plays a role in energy transfer between circuits through electromagnetic induction.
What role does a ferromagnetic core play in self inductance?
A ferromagnetic core increases self inductance by concentrating and enhancing the magnetic field within the coil.
Differentiate between self induction and mutual induction.
Self induction refers to an emf induced in a single coil due to its own changing current, while mutual induction involves the inducing of emf in a secondary coil by the changing current in a primary coil.
What is the significance of the sign in the formula E = -L(dI/dt)?
The negative sign indicates Lenz's law, signifying that the induced emf opposes the change in current creating it.
How is the energy stored in an inductor calculated?
Energy stored in an inductor is calculated by the formula U = (1/2)L I^2, where U is the energy, L is inductance, and I is current.
Why does self inductance make it difficult to switch off current in a circuit?
Self inductance causes a back emf which opposes any change in current, making it difficult to abruptly stop the current.
What analogy is commonly used to explain inductance?
Inductance is often compared to mechanical inertia, where an inductor’s resistance to changes in current is likened to inertia's resistance to changes in velocity.
Explain the concept of back emf in self induction.
Back emf is the induced emf in an inductor when there is a change in current, opposing the original change in the circuit.