Basics

Question 1

power, voltage, resistance formula

Answer 1

P = V²/R

Question 2

converting between power and voltage of diff countries

Answer 2

The resistance of the bulb stays constant, so use P = V²/R to figure it out

Question 3

Electricity

Answer 3

The presence and motion of charged particles

Question 4

Electric current

Answer 4

flow of charged particles

Question 5

Electric charge

Answer 5

Fundamental property of the elementary particles that form the basis of matter

Question 6

What are conductors, insulators and semiconductors?

Answer 6

Classification of solids by their effectiveness in transferring electric charge

Question 7

Conductors are mostly

Answer 7

Metals

Question 8

Insulators are mostly

Answer 8

Nonmetal materials

Question 9

What are semiconductors?

Answer 9

Metalloids with properties in-between/a mixture of those of metals + non-metals

Question 10

Six elements commonly recognised as metalloids

Answer 10

Boron
Silicon
Germanium
Arsenic
Antimony
Tellurium

Question 11

Eg of conductors

Answer 11

copper
aluminium
silver
platinum
bronze
gold

Question 12

Eg of insulators

Answer 12

glass
rubber
plastic
air
varnish
paper
wood
mica
ceramic
certain oils

Question 13

Energy band model of matter

Answer 13

In solids, energy levels form continuous bands of energy rather than discrete energy levels of atoms in isolation, as large no. of atoms are brought together (no. of orbits becomes v large)

Question 14

Fermi level

Answer 14

Highest energy level that an electron can reach or occupy in a material at absolute zero temperature

Question 15

Valence band in solids

Answer 15

highest range of electron energies in which electrons are normally present at absolute zero temp

Question 16

Valence electrons vs conduction electrons

Answer 16

• Valence electrons bound to indiv atoms

- Cond electrons can move freely within atomic lattice of material

Question 17

Band gap

Answer 17

• Separates valence band and conduction band in insulators and semiconductors
• in metals: no energy gap

Question 18

One of the laws of electric charge

Answer 18

Like charges repel each other while unlike charges attract each other

Question 19

Electric charge:

• unit of charge
• symbol

Answer 19

• Coulomb

- C

Question 20

what is one Coulomb?

Answer 20

Amount of electric charge transported in one second by a constant current of one ampere

Question 21

Coulomb’s Law

Answer 21

F ∝ Q₁Q₂/r²

Question 22

Constant of proportionality

Answer 22

1/4πε

Question 23

what is ε

Answer 23

permitivity of space between charges

Question 24

permitivity

Answer 24

property of a medium that accounts for its effect on force between the charges

Question 25

permitivity of free space

Answer 25

-for a vacuum the permitivity is denoted as ε₀

Question 26

Force between charges formula

Answer 26

(1/4πε)(Q₁Q₂/r²)

Question 27

Force between charges and sign

Answer 27

• Force is negative and is of attraction if charges are of opposite sign
• Positive force of repulsion if charges are of same sign

Question 28

Units of permitivity of free space

Answer 28

• Farad per metre (F/m)

- C²/Nm²

Question 29

Electrostatic lines of force diagrams

Answer 29

Like charges: forces tend to divert charges away from each other

Unlike charges: tend to move towards each other

Question 30

Electric field

Answer 30

exists in a region of space in which a stationary charge experiences a force

Question 31

Electric field strength

Answer 31

E, at a point is the force experienced per unit positive charge on a point charge placed at that point

Question 32

Electric field formula

Answer 32

E = F/Q

F = electric force experienced by a particle of charge +Q

Question 33

Electric field strength 0 scalar or vector?

Answer 33

Vector

Question 34

Electric field strength units

Answer 34

N/C