part 4

Question 1

define electrical charge and its unit

Answer 1

1 coulomb = 6.3 x 10^18

Question 2

define electrodynamics

Answer 2

the study of electric charges in motion

Question 3

define electric power

what is it expressed in

Answer 3

electric current through a potential

expressed in watts

Question 4

define electrostatics

Answer 4

the study of stationary electric charges

Question 5

define a dipole

Answer 5

two poles

Question 6

define electromagnetic induction

Answer 6

the production of a current by motion of a conductor through a magnetic field

Question 7

define electrostatic induction

Answer 7

the redistribution of charge in an object caused by the influence of nearby charges

Question 8

define magnetic domain

Answer 8

an accumulation of many atomic magnets with their dipoles aligned

Question 9

define autotransformer

Answer 9

the iron core transformer with on winding

Question 10

define electric potential

Answer 10

the energy that causes electrons to move in a conductor

measured in volts

Question 11

describe an electromagnet

Answer 11

current carrying coil wrapped around a ferromagnetic core

Question 12

explain how magnetic domains can make an object act like a magnet

Answer 12

when the magnet domains align the object is magnetized

Question 13

what is an electric circuit?

Answer 13

when electrons flow is controlled by use of resistance and the conductor is made into a closed path

Question 14

what is the relationship between electric resistance and electric current

Answer 14

inverse relationship

as resistance increases flow decreases and vice versa

Question 15

differentiate between a series and parallel circuit

Answer 15

series - has elements connected in a line along the same conductor
parallel - circuit has bridging lines across conductors

Question 16

differentiate between a direct and alternating current

Answer 16

direct current has flow in one direction along the conductor

alternating has flow that can change directions periodically

Question 17

define volt

Answer 17

measure of electric potential

Question 18

define ampere

Answer 18

measure of electric current

Question 19

define ohm

Answer 19

measure of electric resisitance

Question 20

define watts

Answer 20

measure of electric power

Question 21

define hertz

Answer 21

the number of cycles per second

Question 22

a magnetic field is created by a _______ particle in ______

Answer 22

charged

motion

Question 23

the magnetic field of a charged particle is _________ to the motion of that particle

Answer 23

perpendicular

Question 24

the degreee of magnetism exhibited by a material is related to the number of _______in the outer shell

Answer 24

electrons

Question 25

define naturally occuring magnets

Answer 25

materials in the earth, the earth itself

Question 26

define permanent magnets

Answer 26

artificially produced, charged in an electromagnetic field

Question 27

define electromagnets

Answer 27

wire wrapped around an iron core, a current is applied to create a magnetic field

Question 28

define dimagnetic materials

Answer 28

materials that are unaffected by a magnetic field

Question 29

define ferromagnetic materials

Answer 29

materials that are easily permanently magnetized

Question 30

paramagnetic materials

Answer 30

slightly attracted to a magnet and loosely influenced by an external magnetic field

Question 31

non magnetic materials can be made magnetic by ______

Answer 31

induction

Question 32

the si unit of magnetic field strength is

Answer 32

tesla

Question 33

a coil of wire carrying an electron flow is a

Answer 33

solenoid

Question 34

where would magnetic field be concentrated in a solenoid?

Answer 34

through the centre of the coil

Question 35

to increase that magnetic field one could wrap a coil around a material that is _________ such as _______ to create a device that is _______

Answer 35

ferromagnetic iron electromagnet

Question 36

remember that a key to inducing the flow of an electric current is ______ magnetic field

Answer 36

changing

Question 37

electric current can be induced by magnetic fields of changing intensity, either through self induction or mutual induction, what is the difference between the two

Answer 37

self - when a coil or solenoid induces a voltage by its own changing magnetic field mutual - when a current is induced in a second coil by supplying a varying magnetic field to a primary coil

Question 38

in an xray tube we usually see an induction motor made up of 2 components a rotor with windings and stators what is the purpose of each one

Answer 38

rotors - rotate, it is a series of wire loops that have current induced by the stators stators - electromagnets that are energized in sequence to produce a changing magnetic field

Question 39

what is a generator

Answer 39

a device that converts mechanical energy to electrical energy

Question 40

what is a motor

Answer 40

a device that converts electrical energy to mechanical energy

Question 41

what is a transformer

Answer 41

transforms electric potential and currents into higher or lower intensities, proportional to the number of turns of primary and esconday coils