# Shared Flashcard Set

## Details

PHYS 221 Test 1
N/A
32
Physics
02/16/2009

Term
 The potential is constant throughout a given region of space. What else is true?
Definition
 Electric field is zero.
Term
 Electric field always moves from ___ to ___.
Definition
 positive to negative
Term
 In a region where there is an electric field, the electric forces (due to the electric field) do 5.46 times 10-19 J of work on an electron as it moves from point X to point Y. Which point has a higher potential?
Definition
 Y --> because work is positive
Term
 Why would an electrician working on a circuit keep one hand behind his back?
Definition
 to avoid becoming part of the circuit
Term
 A charged particle enters a mass spec perpendicular to the magnetic field. It's path becomes a ____.
Definition
 spiral
Term
 When charging, Initially, capacitors behave like ___. After a long itme, they behave like ___.
Definition
 wires, open switches
Term
 When discharging, capacitors initially behave like ____. After a long time, the behave like ____.
Definition
 batteries, open switches
Term
 Kirchoff's Junction Rule
Definition
 The sum of currents going into a junction equals the sume of the currents going out.
Term
 Kirchoff's Loop Rule
Definition
 when any closed loop is traversed completely in a circuit, the algebraic sum of the changes in potential equals zero.
Term
 Current is always directed from lower/higher to lower/higher potential.
Definition
 higher to lower
Term
 ____ is defined as charges in motion.
Definition
 current
Term
 ___ is a scalar, signed quantity whose sign corresponds to the direction of motion of net positive charges by convention.
Definition
 current
Term
 A break at any point in a circuit causes what to happen to current?
Definition
 I goes to zero
Term
 Batteries produce fixed ___.
Definition
 Voltage (potential)
Term
 Shape of current
Definition
 continuous loop
Term
 2 resistors wired in series. If there is a current in the first one, then the current in the second one is ___
Definition
 the same as the first one
Term
 A ___ is a charge pump that can maintain a potential difference across two terminals by doing work on the charges.
Definition
 EMF
Term
 Collisions of electrons in matter cause energy transfer to matter which ends up as heat. This process is called ___.
Definition
 Resistive heating
Term
 What is meant by a 60 watt bulb?
Definition
 60 watts of power are dissipated. P=60
Term
 Which has larger resistance, 40W or 60W bulb?
Definition
 40
Term
 A ___ is a device capable of storing electric charge and thus electric potential energy.
Definition
 Capacitor
Term
 Purpose of a capacitor
Definition
 Store up charge and later release it in a controlled way
Term
Definition
 Of two conductors... each holds equal and opposite charge
Term
 In a parallel plate capacitor, when Q is fixed, ___ is constant.
Definition
 E
Term
 ___ is the ability to store Q for little V.
Definition
 Capacitance
Term
 Dialectrics have ____, which can align in a field.
Definition
 dipoles
Term
 A parallel plate capacitor has equal and opposite Q on the plates. if the plates are pulled further apart, the C increases/decreases/remains the same
Definition
 decreases
Term
 A parallel plate capacitor has equal and opposite charge on the plates. If the plates are pulled further apart, the stored energy increases/decreases/remains the same.
Definition
 increases
Term
 Defibrillators are ____.
Definition
 Capacitors
Term
 A change in electric potential energy indicates that ___ is done.
Definition
 work
Term
 Field is parallel/perpendicular to equipotential surface.
Definition
 perpendicular
Term
 Net number of ____ is proportional to net charges enclosed in the surface.
Definition
 field lines
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