physics_current_electricity
Current Electricity
Ohm's LawV∝RV=IR
Drift Velocityvd=-eEm𝜏 where 𝜏=relaxation timeE=electric fieldm=mass of electron
Current density=jj=ne2m𝜏E
Resistance=R=𝜌lA where, 𝜌=Resistivity of material
Conductivity=𝜎=1𝜌
Mobility (πœ‡) is defined as magnitude of the drift velocity per unit electric field.πœ‡=|vd|E
Ammeter: The resistance of Ammeter must be very small compared to other resistances in the circuit. A galvanometer can be converted into Ammeter by connecting a resistor of very low resistance R in parallel.
Voltmeter: A galvanometer can be converted into voltmeter by connecting a resistor of high resistance R in series.
QWhat is Specific resistance ASpecific resistance of a conductor is defined as the resistance offered by conductor per unit length and unit cross-sectional area when the known amount of voltage is applied.Specific Resistance=𝜌=RAL where,𝜌=Resistivity of materialR: resistanceA: cross-sectional areaL: length of the material
QWhich conservation principle is involved in Kirchoff’s second law?AKirchhoff’s second law or voltage law is a consequence of the law of conservation of energy.