Physics 2

which direction do electric fields point?

toward negative charges and away from positive charges

how to calculate the magnitude of an electric field

1. calculate the magnitude of field for each point charge

2. determine the direction that the field is pointing for each charge

3. if pointing in same direction then add, if opposite then substract

If point charges aren’t linear then add like a vector

If a point acts diagonally, then find the magnitude of the field and then convert to x and y components by multiplying by the sin and cos of the respective angle

units for electric field strength

N/C

units of electric flux

(Nm²)/C

For positive charges, electric force goes in the ____ direction as electric field

same

For negative charges, electric force goes in the _______ direction as the electric field

opposite

what is the main difference between electric force and electric field?

electric field is created by one charge. more than one charge can interact at an uncharged point.

an electric force is generated when two charges interact with one another

What is the difference between these two equations?

First one is for discharging/losing charge and the second is for charging/gaining charge

in the formula for magnetic flux, what does the angle theta measure?

the angle between the normal and the field lines.

the “normal” is always perpendicular to the plane of the surface. if the field lines are rotated to be x. degrees with the plane, then you must do 90-x to find theta

rules for concave mirrors when object is outside of focal point

real, inverted (-m)

rules for concave mirrors when object is inside focal point

virtual, upright (+m)