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Bohr’s Atomic Model
- Proposed by Niels Bohr in 1913 to address the limitations of Rutherford’s atomic model.
- Electrons move in specific quantized orbits around the nucleus without radiating energy.
- These orbits are called energy levels or shells, denoted by n (n = 1, 2, 3...).
- The energy of an electron is constant in a specific orbit.
- An electron can move to a higher orbit by absorbing energy or to a lower orbit by emitting energy
- An atom is the smallest unit of matter that retains the properties of an element.
- It consists of a nucleus at the center and electrons orbiting around it.
- The nucleus contains protons (positively charged particles) and neutrons (neutral particles).
- Electrons are negatively charged and occupy distinct energy levels or shells.
- Atoms are electrically neutral because the number of protons equals the number of electrons.
Discover
- A transformer is an electrical device used to change the voltage levels in an AC circuit.
- It operates on the principle of electromagnetic induction and mutual induction between two coils.
Working Principle of a Transformer
- Based on Faraday's laws of electromagnetic induction, a varying current in the primary coil produces a varying magnetic flux.
- This magnetic flux links to the secondary coil through a common core, inducing an EMF in the secondary coil.
- The transformer w
- Lenz's Law explains the direction of the induced EMF and current in electromagnetic induction.
- It is an extension of Faraday's laws of electromagnetic induction, focusing on the conservation of energy.
Lenz’s Law
- Statement: The direction of the induced current is such that it opposes the change in magnetic flux that caused it.
- Mathematically represented as: EMF = -dΦ/dt, where the negative sign signifies opposition to change (as per Lenz’s Law).
- Ensures compliance with t
- Electromagnetic induction is the process of generating an electromotive force (EMF) by changing the magnetic field around a conductor.
- Discovered by Michael Faraday in 1831, this phenomenon is the foundation of modern electrical technology.
Faraday's Laws of Electromagnetic Induction
First Law
- Faraday's First Law: An EMF is induced in a conductor whenever there is a change in the magnetic flux linked with it.
- The change in magnetic flux can be caused by moving the conductor, changing the
Basics of Electromagnets
- An electromagnet is a type of magnet created by passing an electric current through a coil of wire.
- The magnetic field is produced by the electric current, and it disappears when the current is stopped.
- The strength of an electromagnet depends on the number of turns in the coil, the current passing through it, and the presence of a ferromagnetic core.
- Electromagnets are temporary magnets, unlike permanent magnets.
- The dir
Earth's Magnetism
- Earth behaves like a giant magnet with a magnetic field generated by the movement of molten iron and nickel in its outer core.
- The Earth's magnetic field protects us from solar wind and harmful cosmic radiation.
- The magnetic field is strongest near the magnetic poles and weakest near the equator.
- The geomagnetic field resembles that of a dipole tilted by about 11 degrees from the Earth's rotational axis.
- Magnetic field lines eme
Magnets
- A magnet is an object that generates a magnetic field and can attract ferromagnetic materials like iron, nickel, and cobalt.
- Natural magnets are naturally occurring substances like magnetite, while artificial magnets are man-made.
- Magnets have two poles, north and south, where the magnetic force is strongest.
- Like poles repel each other, and unlike poles attract each other.
- Magnets can lose their magnetism through
Electric Power
- Electric power is the rate at which electrical energy is consumed or produced in a circuit.
- The formula for electric power is P = VI, where P is power, V is voltage, and I is current.
- Using Ohm’s law, power can also be expressed as P = I²R or P = V²/R, where R is resistance.
- Its SI unit is the watt (W), where 1 watt = 1 joule/second.
- In household applications, power is often measured in kilowatts (kW).
- The energy consumed i
Series Circuits
- In a series circuit, components are connected end-to-end so that the current flows through each component sequentially.
- The same current flows through all components in a series circuit.
- The total resistance in a series circuit is the sum of individual resistances: R_total = R1 + R2 + R3 + ...