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ELECTRIC, MAGNETISM, DIRECT CURRENT CIRCUIT - Coggle Diagram
ELECTRIC
Electric Current
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Unit of electric current: Ampere, A: 1A = 1C/s
By convention, current is defined as flowing from + to -. Electrons actually flow in the opposite direction, but not all currents consist of electrons.
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Electric power
Since U = qV
Power, P = dU/dt = V(dq/dt)
The time rate at which electric energy is consumed by an electrical device is called electric power: P = VI = I2R = V2/R
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Resistivity
the constant ρ, the Resistivity, is characteristic of the material
The resistance of a wire is directly proportional to its length and inversely to its cross-sectional area
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MAGNETISM
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Torque on a Current Loop
The forces on opposite sides of a current loop will be equal and opposite (if the field is uniform and the loop is symmetric), but there may be a torque:
τ = NIAB sin θ
The quantity NIA is called the magnetic dipole moment, M: M = NIA
Hall Effect
Whenever we place a current carrying conductor in a magnetic field, there is a deflection of the charge carriers due influence of magnetic field in the conductor body. We call this typical phenomenon as Hall effect
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Mass Spectrometer
A mass spectrometer measures the masses of atoms. If a charged particle is moving through perpendicular electric and magnetic fields, there is a particular speed at which it will not be deflected: v = E/B
All the atoms reaching the second magnetic field will have the same speed; their radius of curvature will depend on their mass. 
DIRECT CURRENT CIRCUIT
Voltmeter
Instrument used to measure electric potential difference. Voltmeters measure the electric potential drop across components. The voltmeter is placed in parallel with the component of interest because components in parallel experience the same potential difference
Resistor
Resistor in series:
Req = R1 + R2 + R3
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Resistor in parallel:
1/Req = 1/R1 + 1/R2 + 1/R3
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Kirchhoff's Law
Point Rule: The sum of the currents flowing into a junction is zero.
:ΣIN = ΣOUT
Sign Convention: Inwars currents are positive, outwards currents are negative.
: ΣI = 0
Loop Rule: The sum of e.m.f.,s in any loop equals the sum of the IR products in the same loop.
Sign Convention: e.m.f.'s and currents in direction of travel around a loop are positive. the direction of a voltage source is always away from its positive terminal : ΣV = ΣIR
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Galvanometer
A galvanometer is an electromechanical instrument used for detecting and indicating an electric current. A galvanometer works as an actuator, by producing a rotary deflection of a pointer, in response to electric current flowing through a coil in a constant magnetic field.
Wheatstone Bridge Circuit
