D2, D3, D3 Electric fields, Magnetic fields, Electromagnetic Induction Flashcards
What is an electric field?
A region of space where a stationary charge experiences a force
How can charge be transferred? (4 ways)
- Friction
- Electrostatic Induction
- Contact
- Earthing
What is Coulomb’s law of electrostatics
The magnitude of the force between 2 point charges is directly proportional to the product of the magnitude of the charges and is inversely proportional to the square of their separation
What is the formula for the force between 2 point charges
F=(1/4πe0)(Q1Q2/r^2)
What is electric field strength (E)
the electric force exterted per unit positive charge on a small stationary positive charge placed at that point
E=F/q
What is the formula for E (point charge)?
E=F/q=kQ/r^2
combining with the F equation
What is the formula for E (parallel plates)?
E=∆V/d
V is potential, ∆V is potential difference
What is electric potential energy, Ep?
Electric potential energy of a point charge placed at a point in the electric field is the work done by an external agent in bringing the point charge from infinity to that point
Ep = kQq/r
Ep=Ve x q
What is electric potential, Ve?
Electric potential at a point due to the electril field is the work done per unit positive charge by an external agent in bringing a small test charge from infinity to that point
Ve=kQ/r
Ve=E x r
What is a magnetic field?
a region of space where a small magnet would experience a turning force
What is Faraday’s Law?
The magnitude of the induced emf is directly proportional to the rate of change of magnetic flux linkage
What is Lenz’s Law?
The direction of induced emf is such as to oppose the change in magnetic flux that causes it
What is the formula for emf?
ε=-N∆Φ/∆t = BLv
What is magnetic flux Φ?
the magnetic flux density passing through a plane area normal to the direction of the flux density
Φ=BAcosθ
emf for coil rotating in uniform magnetic field
ε=NBAωcos(ωt)
