Download O Level Physics Formula

O Level Physics Formula
Measurements
Base SI Units
Kg, m, s, A, K, mol
Number Prefix
n (10-9), µ (10-6), m
(10-3), c (10-2),
d (10-1), K (103), M
(106)
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
(m), centi ©, deci (d), kilo
(K), mega (M).
Newton’s Laws of Motion
Newton’s First Law
At equilibrium, the body continues
to stay in its state of rest or of
∑F=0
uniform speed as long as no net
force and no net torque is acting
on the body.
Newton’s Second Law
F= ma
The acceleration of an object is
directly proportional to the net
force acting on it and inversely
proportional to its mass.
Newton’s Third Law
For every force object A acts on
object B, object B will exert an
equal and opposite force on object
A.
Equations in Motion
Average Speed
d=distance,
s = ∆d / ∆t
t= time
x = displacement,
Average Velocity
t= time,
v = ∆x/∆t
slope of distance-time
graph
Acceleration
A = ∆v/∆t
u=initial velocity
v = u + at
½at2
x = ut +
v2 = u2 + 2ax
v = 2𝑔ℎ
1
Forces and Torque
Reaction Forces
Acting in opposite direction.
For example, the ground will
give a reaction force that is
equivalent to the man’s
weight.
Force Resolution on
Ө is the angle between the
Inclined Plane
horizontal surface and the
inclined plane.
Fhorizontal = F cos Ө
Fvertical = F sin Ө
Moment of Force
m=Fd
Rotational Balance
Anticlockwise Moment =
Clockwise Moment
Moment m is the product of
force F and perpendicular
distance from the pivot d.
Condition for body in
rotational balance
Mass, Weight, Density and Pressure
Weight w = mg
Weight w is the product of
mass by gravitational field
strength
Density
Density d is given by the
ratio of mass m over volume
𝑚
V.
d=
𝑉
Pressure
g=gravitational
constant=9.81 m/s2
h = height
Pressure P is the ratio of
force F over area A.
𝐹
P= 𝐴
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Pressure of liquid column Pressure h is proportional to
P = ρgh
density ρ, height of column
h and gravitational field
strength g.
O Level Physics Formula
Work Done
W = Fd
Light and Optics
Law of Reflection The angle of incident Ө1 is
equal to the angle of reflection
θ1 =θ2
Ө2. Both are with respect to
the perpendicular normal of
the surface of the mirror.
Work and Energy
F= force, d= distance
θ= angle between Force
& distance
Power
P= W/t = Fv
Kinetic Energy
1
Ek= 2 mv2
t=time
m=mass
v=velocity
Gravitational Energy g=gravity=9.81 m/s2
Ep = mgh
h = height
Conservation of
Energy
E 1 = E2
Period
1
T=𝐹
Snell’s Law
(refraction)
n1sinθ1 =n2sinθ2
The angle of incident Ө1 and
angle of refraction Ө2 is with
respect to the perpendicular
normal of the surface between
the two medium.
Critical Angle
𝑛
sinθc =𝑛1
The critical angle θc is the
angle of incidence beyond
which total internal reflection
occurs. The index 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.
2
E1=Energy Before,
E2=Energy After
Energy cannot be
created or destroyed,
only transformed or
converted into other
forms. The total energy
of a closed system
remains the same.
Wave Velocity
v=fλ
2
Index of Refraction The higher the index of
𝐶
refraction is for a medium, the
n =𝑉
slower is the speed of light v
in the medium. c is the speed
of light in vacuum.
Focal Length of a
mirror
Waves
The velocity of a wave
v is the product of its
frequency f and
wavelength λ.
1
f = 2r
Period T is the inverse
of frequency f.
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For a spherical mirror, the
focal length is half of the
radius of curvature.
O Level Physics Formula
Thermal Energy
Thermal Energy &
Energy is required to
Specific Heat Capacity
increase the temperature of
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.
& Latent Heat
Lfusion is the latent heat of
For melting,
fusion.
E = m Lfusion
Lvaporization is the latent heat
of vaporization.
For boiling,
m is the mass.
E = m Lvaporization
Current
I = ∆C / ∆t
Ohm’s Law
Resistance
R=V/I
Resistance of a
wire
R = ρL/A
Resistance Series
Rtotal = R1 + R2
Resistance
Parallel
1
𝑅total
1
Electric Circuits
C=Charge t=time
V=voltage,
R= resistance,
I = current
ρ = resistivity
L = length of wire
A = cross sectional area
Resistors in series have resistance
added up.
Resistors in parallel utilizes the
reciprocal rule.
1
=𝑅 +𝑅
1
2
Electric Power
P = VI
= V2/R
= I2R
Combining ohm’s law the power P
can be calculated using any
combination of these three equation
variations.
Electrical Energy
E = Pt = VIt
Electrical energy can be calculated
by the product of power and time.
P = Power
t = time
V=voltage,
I = current
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Transformer
V𝑝 n𝑝
Vs = ns
3
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.