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Physics Test Notes

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Society has become increasingly dependent on electricity over the last 200 years Random Keywords: Independent Variable: variable that is changed Dependent Variable: thing that changes with independent variable, it is what you measure Control Variables: variable held constant for reference Validity or valid: the extent to which a measurement accurately reflects the concept, which is intended to measure Accuracy: how close your measurement or results are to the true value Reliability: the extent to which a measurement yields consistent stable and uniform results over repeated observations or measurements. Domestic energy and how it has changed * The first sources of electrical energy were batteries, which …show more content…

ric Field Definition of electric field (E) at a point in space: the electric force (F) acting on a positive test charge placed at that point divided by the magnitude of the test charge q0 E = F ----- q0 E = F ----- q0 * Where k is a constant called coulomb constant * The unit of charge in SI units is the (C) * k = (approximately) 9.0 x 109 N.m2/C2 Electric Field * Electric field lines are a convenient way to visualize electric field patterns * It is shown by drawing the electric field at any point (Einstein just got smarter) * If the lines of force are close together it indicated that the field is strong and therefore where the field lines are further apart it indicates that the field is weak The rules for drawing electric field lines for any charge distribution * You must always begin on a positive charge and terminate on a negative one, infinity may be considered in the case of an excess charge * The number of lines drawn leaving a positive charge or approaching a negative charge is proportional to the magnitude of the charge * No field line can cross Electric field lines for a positive point charge * The lines in an electric field are not actually two dimensional but are directed radially outward from the charge in all directions * Since a positive test charge placed in this field would be repelled by the charge q, the line are directed radially away from the

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