electricity definitions

Question 1

electric charge

Answer 1

electric charge indicates if a body has an excess or a deficiency of electrons

Question 2

conductor

Answer 2

a conductor is any substance through which electric charge can flow

Question 3

insulator

Answer 3

an insulator is any substance through which electric charge cannot flow

Question 4

point discharge

Answer 4

point discharge is the phenomenon where ions in the air are either strongly attracted or repelled from the tip of a charged conductor and move towards or away from it

Question 5

electric field

Answer 5

an electric field is the region of space in which electric charges at rest experience an electrostatic force

Question 6

electric field line

Answer 6

an electric field line is the line along which a positive charge would move if placed in the electric field

Question 7

electric field strength

Answer 7

the electric field strength at a point in an electric field is the force per unit positive charge at that point

Question 8

potential difference

Answer 8

the potential difference (voltage) between 2 points is the work done in moving a charge of one coulomb from one point to another

Question 9

electromotive force

Answer 9

the electromotive force (emf) is a voltage that is applied to a circuit

Question 10

capacitance

Answer 10

capacitance is the ratio of the charge on a capacitor to the potential difference applied across it

Question 11

capacitor

Answer 11

a capacitor is an electrical device capable of storing electric charge

Question 12

electric current

Answer 12

electric current is the flow of electric charge

Question 13

resistance

Answer 13

the resistance of an object is the ratio of voltage across it to the current through it

Question 14

resistor

Answer 14

a resistor is a device that converts electrical potential energy to another form

Question 15

resistivity

Answer 15

resistivity is a constant associated with the resistance of a body, it is equal to the product of the resistance of the body and its cross sectional area divided by its length

Question 16

semiconductor

Answer 16

a semiconductor is a substance whose resistivity is between that of a good conductor and a good insulator

Question 17

intrinsic conduction

Answer 17

intrinsic conduction is the movement of charge through a pure semiconductor

Question 18

extrinsic conduction

Answer 18

extrinsic conduction is the movement of charge through a doped semiconductor

Question 19

doping

Answer 19

doping is the addition of a small amount of another element to pure semiconductor to increase its conductivity

Question 20

n-type semiconductor

Answer 20

an n-type semiconductor is one in which the impurity added produces more free electrons available for conduction

Question 21

p-type semiconductor

Answer 21

a p-type semiconductor is one in which the impurity added produces extra holes which are available for conduction

Question 22

diode

Answer 22

a diode (p-n junction) is a semiconductor device that allows current to flow in one direction only

Question 23

LDR

Answer 23

a LDR (light dependant resistor) is a semiconductor device whose resistance varies from a high value in the dark to a lower value in bright light

Question 24

thermistor

Answer 24

a thermistor is a semiconductor devise whose resistance decreases rapidly with increasing temperature

Question 25

magnetism

Answer 25

magnetism is a phenomenon by which certain materials exert attractive or repulsive forces on the other materials

Question 26

magnetic field

Answer 26

a magnetic field is the region of space where magnetic forces can be felt

Question 27

magnetic field line

Answer 27

magnetic field line indicates the direction a 'magnetic North' would travel in a magnetic field if free to do so

Question 28

magnetic flux density

Answer 28

magnetic flux density is a measure of the strength of the magnetic field

Question 29

electromagnetic induction

Answer 29

electromagnetic induction is where an emf is induced by a change in the magnetic flux linking a circuit

Question 30

magnetic flux

Answer 30

magnetic flux is the total amount of magnetic field in a given region, it is the product of magnetic flux density and area

Question 31

alternating current

Answer 31

an alternating current is an electric current whose direction reverses periodically

Question 32

direct current

Answer 32

a direct current is an electric current that flows continuously in the same direction

Question 33

mutual induction

Answer 33

mutual induction is where a changing magnetic field in one coil induces an emf in another coil

Question 34

transformer

Answer 34

a transformer is an electrical device used to change the voltage of a.c power supplies

Question 35

self induction

Answer 35

self induction is where a changing magnetic field in a coil induces a emf in the coil itself

Question 36

inductor

Answer 36

an inductor is an electrical device used to induce a back emf