IGCSE Formula and Key Facts

Question 1

IGCSE Formula and Key Facts

speed

Answer 1

distance travelled

time taken

Question 2

IGCSE Formula and Key Facts

s =

Answer 2

d

t

Question 3

IGCSE Formula and Key Facts

acceleration

Answer 3

change in velocity

time taken

Question 4

IGCSE Formula and Key Facts

a =

Answer 4

(v-u)

t

Question 5

IGCSE Formula and Key Facts

Hooke’s law for springs

Answer 5

Force applied to a spring is proportional to its extension, up to the limit of proportionality

Question 6

IGCSE Formula and Key Facts

For a spring,

F =

Answer 6

kx

Question 7

IGCSE Formula and Key Facts

Resultant force on an object

Answer 7

mass x acceleration

or

the vector sum of all the individual forces acting on it

Question 8

IGCSE Formula and Key Facts

For an accelerating object with a resultant force on it,

F =

Answer 8

ma

Question 9

IGCSE Formula and Key Facts

weight

Answer 9

mass x gravitational field strength

Question 10

IGCSE Formula and Key Facts

W =

Answer 10

mg

Question 11

IGCSE Formula and Key Facts

What is the gravitational field strength at the surface of the Earth (with units)

Answer 11

10 N/kg

(approximately)

Question 12

IGCSE Formula and Key Facts

density

Answer 12

mass

volume

Question 13

IGCSE Formula and Key Facts

**ρ = **

Answer 13

m

V

Question 14

IGCSE Formula and Key Facts

moment

Answer 14

force x perpendicular distance to the line of action of the force

Question 15

IGCSE Formula and Key Facts

moment of a force =

Answer 15

Fd

Question 16

IGCSE Formula and Key Facts

The Principle of Moments

Answer 16

If a body is in equilibrium,

sum of clockwise moments = sum of anticlockise moments

F₁d₁ + F₂d₂….= F₃d₃ + F₄d₄…

Question 17

IGCSE Formula and Key Facts

current (in amps)

Answer 17

charge (in coulombs)

time (in seconds)

Question 18

IGCSE Formula and Key Facts

Q =

Answer 18

It

Question 19

IGCSE Formula and Key Facts

I =

Answer 19

Q

t

Question 20

IGCSE Formula and Key Facts

Refractive index of a material

Answer 20

speed of light in a vacuum

speed of light in the material

Question 21

IGCSE Formula and Key Facts

n =

Answer 21

sin i

sin r

Question 22

IGCSE Formula and Key Facts

Electromagnetic spectrum in order of decreasing wavelength

Question 23

IGCSE Formula and Key Facts

frequency (in Hz)

Answer 23

number of waves passing per second

Question 24

IGCSE Formula and Key Facts

f =

Answer 24

1

T

(T= the period of the, i.e. the time for one complete wave)

Question 25

# IGCSE Formula and Key Facts wave speed (in m/s)

Answer 25

frequency (in Hz) x wavelength (in m)

Question 26

# IGCSE Formula and Key Facts For a wave **v =**

Answer 26

**fλ**

Question 27

# IGCSE Formula and Key Facts The prefix **M** in front of a unit means?

Answer 27

"mega" / million e.g. **1Mz = 1,000,000 Hz**

Question 28

# IGCSE Formula and Key Facts **E_GPE =**

Answer 28

**mgΔh**

Question 29

# IGCSE Formula and Key Facts **E_KE = **

Answer 29

**_mv²_** **2**

Question 30

# IGCSE Formula and Key Facts Efficiency

Answer 30

_useful energy_ ( x 100%) total energy supplied

Question 31

# IGCSE Formula and Key Facts Work done against a force

Answer 31

force x distance moved against the force

Question 32

# IGCSE Formula and Key Facts **W =**

Answer 32

**Fd**

Question 33

# IGCSE Formula and Key Facts Power

Answer 33

_energy transferred_ time taken

Question 34

# IGCSE Formula and Key Facts **P**

Answer 34

**_E_** **t**

Question 35

# IGCSE Formula and Key Facts **E =** (in terms of power)

Answer 35

**Pt**

Question 36

# IGCSE Formula and Key Facts Pressure

Answer 36

_force_ area the force is applied over

Question 37

# IGCSE Formula and Key Facts **p =**

Answer 37

**_F_** **A**

Question 38

# IGCSE Formula and Key Facts The SI units of pressure are?

Answer 38

pascal _or_ newtons per square metre **Pa N/m²** 

Question 39

# IGCSE Formula and Key Facts **p =** (due a liquid of depth of **h**)

Answer 39

**hρg**

Question 40

# IGCSE Formula and Key Facts Boyle's Law for a fixed mass of gas at a constant temperature in locations **₁** and **₂**

Answer 40

**p₁V₁ = p₂V₂**

Question 41

# IGCSE Formula and Key Facts Energy required to change state **E =**

Answer 41

**mL**

Question 42

# IGCSE Formula and Key Facts Energy required to raise the temeprature of an object **E =**

Answer 42

**mc(θ₁-θ₂)** _or_ **mcΔT**

Question 43

# IGCSE Formula and Key Facts Units of specific heat capacity

Answer 43

**J/(kg ****°C****)**

Question 44

# IGCSE Formula and Key Facts Electrical energy transferred **E =**

Answer 44

**QV**

Question 45

# IGCSE Formula and Key Facts Resistance of a component in an electric circuit

Answer 45

_Potential Difference across the component_ current through the component

Question 46

# IGCSE Formula and Key Facts **V =**

Answer 46

**IR**

Question 47

# IGCSE Formula and Key Facts Electrical power **P =**

Answer 47

**IV**

Question 48

# IGCSE Formula and Key Facts Energy transferred by an electric current **E =**

Answer 48

**ItV**

Question 49

# IGCSE Formula and Key Facts The transformer equation

Answer 49

**_V__p = _N__p** **V_s N_s**

Question 50

# IGCSE Formula and Key Facts Assuming a transformer is 100% efficient, the power on either side is linked by the equation

Answer 50

**V_pI_p = V_sI_s**

Question 51

# IGCSE Formula and Key Facts For resistors in series, **R_{total =}**

Answer 51

**R₁ + R₂ + ...**

Question 52

# IGCSE Formula and Key Facts For resistors in parallel, **_1_ = ** **R_total**

Answer 52

**_1_ + _1_ + ...** **R₁ R_{2          .}**

Question 53

# IGCSE Formula and Key Facts The total Potential Difference across components in series the same branch of an electric circuit

Answer 53

**= V1 + V2 + ...**

Question 54

# IGCSE Formula and Key Facts The sum of the currents flowing into a junction in an electric circuit

Answer 54

= the sum of all the currents flowing out of the junction