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O Level
Physics Formula Sheet
Measurements
Mass SI Unit is Kilogram
(kg).
Length SI unit is metre (m).
Time SI Unit is second (s).
Current SI unit is Ampere
(A). Temperature SI unit is
Kelvin (K).
Amount of substance is
molar (mol).
nano (n), micro (µ), milli
Number Prefix
n (10-9), µ (10-6), m (10-3), c (m), centi ©, deci (d), kilo
(10-2), d (10-1), K (103), M
(K), mega (M).
(106)
Equations in Motion
d=distance,
Average Speed
s = ∆d / ∆t
t= time
x = displacement,
Average Velocity
v = ∆x/∆t
t= time,
slope of distance-time graph
Acceleration
A = ∆v/∆t
v = u + at
u=initial velocity
x = ut + ½ at2
g =gravitational
v2 = u2 + 2ax
constant=9.81 m/s2
h = height
v = 2gh
Base SI Units
Kg, m, s, A, K, mol
Newton’s Laws of Motion
At equilibrium, the body
Newton’s First Law
→
continues to stay in its state
∑F = 0
of rest or of uniform speed as
long as no net force and no
net torque is acting on the
body.
The acceleration of an object
Newton’s Second Law
F= ma
is directly proportional to the
net force acting on it and
inversely proportional to its
mass.
O-Levels Physics Formula Sheet
For every force object A acts
on object B, object B will
exert an equal and opposite
force on object A.
Forces and Torque
Acting in opposite direction.
Reaction Forces
For example, the ground will
give a reaction force that is
equivalent to the man’s
weight.
Ө is the angle between the
Force Resolution on
horizontal surface and the
Inclined Plane
inclined plane.
Fhorizontal = F cos Ө
Fvertical = F sin Ө
Newton’s Third Law
Moment m is the product of
force F and perpendicular
distance from the pivot d.
Condition for body in
rotational balance
Moment of Force
m=Fd
Rotational Balance
Anticlockwise Moment =
Clockwise Moment
Mass, Weight, Density and Pressure
Weight w is the product of
Weight
w = mg
mass by gravitational field
strength
Density d is given by the
Density
m
ratio of mass m over volume
d=
V
V.
Pressure P is the ratio of
Pressure
F
force F over area A.
P=
A
Gravitational Energy
Ep = mgh
Conservation of Energy
E1 = E2
Energy cannot be created or
destroyed, only transformed
or converted into other
forms. The total energy of a
closed system remains the
same.
Thermal Energy
Energy is required to
Thermal Energy &
increase the temperature of
Specific Heat Capacity
E= m s ∆T
matter. m is the mass, s is the
specific heat capacity and T
is the temperature.
Energy is required to matter
Thermal Energy
to change state. Lfusion is the
& Latent Heat
For melting,
latent heat of fusion while
E = m Lfusion
Lvaporization is the latent heat
of vaporization.
For boiling,
m is the mass.
E = m Lvaporization
Wave Velocity
v=fλ
Period
T=
Pressure h is proportional to
density ρ, height of column h
and gravitational field
strength g.
Work and Energy
F= force, d= distance
θ=angle between Force &
distance
t=time
Pressure of liquid column
P = ρgh
Work Done
W = Fd
Power
P= W/t = Fv
Kinetic Energy
Ek= 1 mv 2
g = gravity=9.81 m/s
h = height
E1=Energy Before,
E2=Energy After
1
f
Waves
The velocity of a wave v is
the product of its frequency f
and wavelength λ.
Period T is the inverse of
frequency f.
M=mass
v=velocity
2
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Prepared by Education Haven
Find an experienced Physics Tutor to go through these formulas? Call us at 6219-1272 or visit http://matchtutor.com.sg to find out more.
Light and Optics
The angle of incident Ө1 is equal to
the angle of reflection Ө2. Both are
θ1 = θ 2
with respect to the perpendicular
normal of the surface of the mirror.
The angle of incident Ө1 and angle
Snell’s Law
of refraction Ө2 is with respect to
(refraction)
the perpendicular normal of the
n1 sin θ1 = n2 sin θ 2
surface between the two medium.
The critical angle θc is the angle of
Critical Angle
incidence beyond which total
n
sin θ c = 2
internal reflection occurs. The index
n1
of refraction for the medium in
which the incident ray is traveling is
n1, the index of refraction for the
second medium which the refracted
ray is traveling is n2.
Index of Refraction The higher the index of refraction is
for a medium, the slower is the
c
speed of light v in the medium. c is
n=
v
the speed of light in vacuum.
The Lens Equation The focal length of the lens f is:
•
Positive for a converging
1
1 1
+ =
lens
do di f
•
Negative for a divergent
lens
The object distance do is:
•
Positive if it is on the side
of the lens from which the
light is coming
•
Negative if on the
opposite side
Law of Reflection
Magnification
m=
hi
d
=− i
ho
do
The image distance di is:
•
Positive if it is on the
opposite side of the lens
from which the light is
coming
•
Negative if on the same
side
For an upright image, the
magnification m is positive and for
an inverted image m is negative.
O-Levels Physics Formula Sheet
For a spherical mirror, the focal
length is half of the radius of
curvature.
Focal Length of a
mirror
f =
1
r
2
Transformer
Current
I = ∆C / ∆t
Ohm’s Law
Resistance
R=V/I
Resistance of a
wire
R = ρL/A
Electric Power
P = VI
= V2/R
= I2R
Electronic Circuits
C=Charge
t=time
V=voltage,
R= resistance,
I = current
ρ = resistivity
L = length of wire
A = cross sectional area
Combining ohm’s law the power P
can be calculated using any
combination of these three equation
variations.
Electrical Energy
E = Pt = VIt
Root Mean Square
Voltage & Current
& Power
Vo
I
, I rms = o
2
2
I 2R 1
2
= I rms
R= 0 = P
2
2
Vrms =
Prms
Resistance in Series
Rtotal = R1 + R2 + R3
Resistance in
Parallel
1
1
1
1
=
+
+
Rtotal R1 R2 R3
Kirchoff’s First
Law
inco min g
∑I =
outgoing
∑I
Kirchoff’s Second
Law
Electrical energy can be calculated
by the product of power and time.
For an AC circuit, the root-meansquare (rms) values can be
calculated from the peak values.
Prms= 0.5 Pmax
Resistance in series adds up. Having
more obstacles along the path for
current means more resistance.
Resistance in parallel takes the
reciprocal. Parallel path for current
to go through means lesser
resistance.
Sum of all incoming currents at a
junction is the same as sum of all the
outgoing current at a junction.
supplied by the power supply.
∑V = EMF
Vp
Vs
=
np
ns
Electromagnetism
The ratio of the voltage Vp and Vs
in a transformer is proportional to
the ratio of the number of coils np
and ns.
Right Hand Grip
Rule
I is the current.
B is the magnetic field.
Fleming’s Left Hand
Rule (Motor Rule)
Thumb is for the
motion. Index finger is
for the magnetic field.
Second finger is for the
current.
Fleming’s Right
Hand Rule
(Generator)
Thumb is for the
motion. Index finger is
for the magnetic field.
Second finger is for the
current.
Sum of all potential difference V in
components of a circuit is equal to
the electromotive force EMF
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