charging, by rubbing and induction
printing processes, photocopiers, laser printers, spray painting
potential hazards:, sparks, fires
positive and negative charges:, forming electric fields
obey laws of electrostatics, like charges repel, unlike charges attract.
electromotive force, emf, effective emf of cells in series equal to sum of emfs for individual cells
potential difference, V, is related to V=IR, ohm's law, V/I=constant
direction of conventional current is opposite to the direction of flows of electrons
is related to:
potential divider using, input transducer, e.g., thermister, LDR
parrallel circuit, a) current from the source is the sum of the current from the separate branches, b) potential differences across separate parallel branches are the same
series circuit, a) current at every point is the same, b) potential difference across the whole circuit is the sum of potential differences across each component
energy, E= VIT
energy unit, kWh
using switches, fuses, circuit breakers, earth wireand double insulation.
damaged insulation, overheating of cables, damp conditions
like poles repel, unlike poles attract.
not found in non magnetic materials
found in magnetic materials, may be permanent or temporary magnet, are used in circuit breakers and magnetic relays, have magnetic field, undergo magnetisation or demagnetisation
electric bell and circuit breaker
magnetic field due to current in straight wires, flat coil and solenoid
direction is determined by fleming's left hand rule
results in turning effect on a current carrying coil., is used in electric motor, is increased by:, .increasing number of turns in coil, . increasing the current, .using an iron core