5.3 Electric Fields Flashcards
1
Q
Define electric field strength
A
electric field strength at a point is equal to the force which would be produced on a test charge of 1C at that point
2
Q
Define coulomb’s law
A
Between every 2 pt charges there exists an electrical force that is directly proportional to the product of the charges and inversely proportional to the square of their separation
3
Q
What is the value of the permittivity of free space
A
8.85 x 10^-12 C^2N^-1m^-2
4
Q
What are the 3 similarities between electric and magnetic fields
A
- electric/grav field around an isolated pt charge decreases in proportion to square of distance 1/r^2
- both fields around a charged sphere are radial
- both have fields of infinite range
5
Q
What are the 3 differences between electric and magnetic fields
A
- Gravitational field around an isolated pt mass is always radially inwards, electric field is radially outwards if pt mass is positively charged
- impossible to shield an object from gravitational field, can shield objects from electric fields
- Gravity acts on masses, electric fields act on charges