Motors and magnetic forcesÃÂMotor effect & F = BILoA current carrying conductor in a magnetic field experiences a force.
oF = nBIL sin ÃÂ¨F = force on conductor (N)n = number of coilsB = magnetic field strength (T)I = current in conductor (A)ÃÂ¨ = angle between conductor and magnetic field.
ÃÂConductor right angle to field = strong. Parallel = no force.
ÃÂForce between current carrying wiresoAmpereÃÂs Law: F = k I1 I2 ldF = force between two wires (N)k = ampereÃÂs constant = 2.0 X 10-7 (NA-2)I1 , I2 = current in wires (A)l = length of parallel wires (m)d = distance between wires (m)oCurrent in same direction = attractive force.
oCurrent in opposite direction = repulsive force.
ÃÂTorque on a loopoTorque = turning effect of a force.
oT = Fd = force x distance from pivot point.
oT = nBIA cos ÃÂ¨T = torque ÃÂ¨ = angle between plane of loop and mag fieldn = no.
of coilsB = magnetic field strength (T)I = current through coil (A)A = area of coil (m2)ÃÂDC Electric Motor:ÃÂLoudspeaker: Current flows through coil attached to cardboard coil. Current varies with desired sound. Coil in permanent magnetic field, coil moves due to motor effect, coil moves cardboard, produces sound.
ÃÂGalvanometer:Current flows through coil attached to spring and needle. Coil surrounded by magnetic field, moves. Depending on size of current, moves till spring stops counteracts the motor affect. Needle points to size of current.
The generatorÃÂFaradayÃÂs discovery of induction.
oMoved a magnet near a coil of wire.
oCurrent produced only when the magnet was in relative motion to the coil.
ÃÂMagnetic flux & flux densityoMagnetic flux = amount of magnetic field passing through an areaoÃÂ¤ = BA cos ÃÂ¨ÃÂ¤ = phi = magnetic fluxB = magnetic field strength (T) = magnetic flux densityA = area...