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