General electrostatics Flashcards
When we have a symetrical shape, what law is useful?
Gauss’ law
When using Gauss’ law, what does LHS become when there is symmetry?
Exsurface area of the shape
How are potential and E field related?
Potential = -integral of E with respect to L
When doing simpler question, what do we need to consider?
Everything is in terms of the changing variable
When we have a solid sphere, how do we find the E field outside?
Treat sphere as a point charge
When we have a solid sphere, how do we calculate the E field inside?
Use Gauss’ law and Qencl is the ratio of the volumes of the surface and the guassian surface
What happens if sphere has a non uniform charge density?
Qencl is found by using a volume integral on the charge density. Find dV in terms of dr
Easiest way to find potential in an xy problem?
Find potential at each point with a charge and then vector sum them
What are the two ways to find work done?
Either find potential at two seperate points and find difference or -q x integral of E x dl
Important point when finding energy density?
We might have to find dU and then integrate it
E field inside a hollow sphere?
0
Electric potential inside a hollow sphere?
We have to find integral of 0 x dr
Capacitance of a sphere?
C = 4 x pi x epsilon x r
What technique do we use when another charge is introduced into a system?
Superposition
What does the electric field outside a sphere depend on?
Charge and distance from centre of sphere
