3.5 Electricity

Question 1

Charge carriers

Answer 1

Charged particles that move through substance when PD applied across it

Question 2

Kirchoff’s 1st Law

Answer 2

Current passing through 2 or more components in series is the same through each component -> At a junction the total current in = total current out

Question 3

Kirchoff’s 2 Law

Answer 3

2 or more components in series - total PD across all the components is = to sum of the PD’s across each component -> Sum of emf’s around complete loop = sum of PD’s around the loop

Question 4

Critical temperature

Answer 4

Temperature at or below which a superconducting material has zero resistivity

Question 5

electrolysis

Answer 5

process of electrical conduction in a solution or molten substance due to charged ions moving to oppositely charged electrode

Question 6

electrolyte

Answer 6

solution that conducts electricity

Question 7

emf

Answer 7

electrical energy per unit charge produced inside electrical source

Question 8

electron volt

Answer 8

work done when an electron is moved through a PD of 1V

Question 9

internal resistance

Answer 9

resistance inside the source of electrical energy - loss of PD per unit current in the source when current passes through it

Question 10

light-dependent resistor

Answer 10

resistance decreases in light

Question 11

negative temperature coefficient

Answer 11

resistance of a semiconductor decreases when its temperature is increased

Question 12

Ohm’s Law

Answer 12

PD across a metallic conductor is proportional to the current - if physical conditions remain constant

Question 13

positive temperature coefficient

Answer 13

resistance of material increases when its temperature is increased

Question 14

potential difference

Answer 14

work done per unit charge between 2 points when charge moves from one to the other

Question 15

potential divider

Answer 15

2 or more resistors in series connected to a source of pd

Question 16

potential energy

Answer 16

energy of an object due to its position

Question 17

power

Answer 17

rate of energy transfer

Question 18

resistance

Answer 18

V/I

Question 19

resistivity

Answer 19

resistance per unit length x area of cross section

Question 20

semiconductor

Answer 20

substance in which the number of charge carrier increases as the temperature increases

Question 21

sensitivity of an instrument

Answer 21

output reading per unit input

Question 22

specific charge

Answer 22

charge to mass ratio

Question 23

supercondctor

Answer 23

material that has zero electrical resistance

Question 24

terminal pd

Answer 24

pd across the terminals of a power supply

Question 25

terminal speed

Answer 25

maximum speed reached by an object when the drag force is equal and opposite to the force causing the motion

Question 26

thermistor

Answer 26

resistor which is designed to have a resistance that changes with temperature

Question 27

Fleming's Left hand rule

Answer 27

rule relating the force, magnetic field and current all acting at right angles to eachother on a current carrying conductor in a magnetic field

Question 28

Fleming's Right hand rule

Answer 28

rule relating force, magnetic field and current of a conductor when it cuts across magnetic field and an emf is induced in it