Electromagnetism Flashcards
Describe an experiment to validate Faraday’s Law
Setup a magnet on a variable speed motor, near a coil connected to an oscilloscope. Vary speed of rotation, expect to see amplitude increase and period decrease. Measure maximum EMF, use V/cm scale setting. Measure peak to peak distance on graticule, use s/cm time base setting. Record V, T and calculate f = 1/T. Plot V vs f and see straight line through origin.
Define magnetic flux density (magnetic field strength).
magnetic flux in an area taken perpendicular to the magnetic flux’s direction
What rule is used to determine the direction of the force experienced b a current-carrying conductor in a magnetic field?
Fleming’s left-hand rule.
What is 1 Tesla?
When a wire carrying a current of 1 ampere placed perpendicular tto the magnetic field experiences a force of 1N per meter of its length.
State Faraday’s law.
The magnitude of the induced emf is directly proportional to the rate of change of magnetic flux linkage.
State Lenz’s law.
The direction of the induced emf or current is always such as to oppose the change producing it.
State the equation linking force, flux density, current and length
F=BIL
What is magnetic flux?
A measure of the magnetic field strength, draw as a set of lines whose density is proportional to the field
strength. Measured in Webers (Wb).
What is 1 Weber?
The number of flux lines through a 1m^2
area in a field of strength 1T
What is magnetic flux linkage?
The product of the magnetic field strength and the number of turns in a coil.
What is electromagnetic intensity?
The electromagnetic power per unit area.
What is a continuous spectrum?
A spectrum in which all visible frequencies or wavelengths are visible.
What is a photon?
A quantum of electromagnetic energy.
