List of data, formulae and relationships
Data
molar gas constant
R = 8.31 J K-1 mol-1
Avogadro constant
acceleration due to gravity
NA = 6.02 × 1023 mol-1
g = 9.81 m s-2 (close to the Earth)
universal gravitational constant
speed of light in vacuum
charge of electron
electron rest mass
permittivity of free space
permeability of free space
G = 6.67 × 10-11 N m2 kg-2
c = 3.00 × 108 m s-1
e = 1.60 × 10-19 C
me = 9.11 × 10-31 kg
εo = 8.85 × 10-12 C2 N-1 m-2
µo = 4π × 10-7 H m-1
u = 1.661 × 10-27 kg (1 u is equivalent to 931 MeV)
atomic mass unit
astronomical unit
light year
parsec
AU = 1.50 × 1011 m
ly = 9.46 × 1015 m
pc = 3.09 × 1016 m = 3.26 ly = 206265 AU
Stefan constant
Planck constant
σ = 5.67 × 10-8 W m-2 K-4
h = 6.63 × 10-34 J s
Rectilinear motion
Mathematics
For uniformly accelerated motion :
Equation of a straight line y = m x + c
v = u + at
s = ut +
Arc length = r θ
Surface area of cylinder = 2 π r h + 2 π r 2
1 2
at
2
v 2 = u 2 + 2a s
Volume of cylinder
= πr2 h
Surface area of sphere
= 4πr2
Volume of sphere
=
sin θ ≈ tan θ ≈ θ (in radians)
For small angles,
A1.
E = m c ∆T
energy transfer
A2.
E = l∆m
energy transfer
during heating and
cooling
during change of state
D2.
D3.
HKDSE Physics Formulae P.1
E=
4 3
πr
3
Q
4πε o r 2
E=
V
d
electric field due to a
point charge
electric field between
parallel plates
(numerically)
A3.
A4.
A5.
PV = n R T
PV =
1
N m c2
3
3 RT
2N A
EK =
equation of state for
an ideal gas
kinetic theory
R = R1 + R2
resistors in series
D6.
1
1
1
=
+
R R1 R2
resistors in parallel
D7.
P = I V = I 2R
power in a circuit
D8.
F = BQv sin θ
force on a moving
charge in a magnetic
field
gravitational potential
energy
D9.
F = BIl sin θ
kinetic energy
D10.
mechanical power
D11.
molecular kinetic
theory
∆v ∆ p
=
Force
∆t
∆t
F =m
B2.
moment = F × d moment of a force
Ep = m g h
B4.
EK =
B5.
1
mv2
2
P = Fv
2
B6.
a=
v
= ω2 r
r
centripetal
acceleration
D12.
B7.
F=
G m1 m2
r2
Newton’s law of
gravitation
D13.
C1.
∆y=
λD
a
C2.
d sin θ = n λ
C3.
1 1 1
+ =
u v f
D1.
F=
Q1 Q2
4π ε o r 2
resistance and
resistivity
D5.
equation
B1.
B3.
ρl
A
R=
D4.
fringe width in
double-slit
interference
B=
µo I
2πr
µ o NI
l
∆Φ
ε=N
∆t
B=
VS N S
≈
VP N P
E1.
N = Noe
diffraction grating
equation
E2.
t1 / 2 =
equation for a single
lens
E3.
A=kN
E4.
∆ E = ∆ mc2
Coulomb’s law
HKDSE Physics Formulae P.2
−k t
ln 2
k
force on a current
carrying conductor in
a magnetic field
magnetic field due to
a long straight wire
magnetic field inside
long solenoid
induced e.m.f.
ratio of secondary
voltage to primary
voltage in a
transformer
law of radioactive
decay
half-life and decay
constant
activity and the
number of undecayed
nuclei
mass-energy
relationship
Astronomy and Space Science
U =−
GMm
r
P = σ AT 4
∆f
∆λ
v
≈ ≈
fo
c
λo
Atomic World
gravitational
potential energy
1
2
me v max
= h f −φ
2
Einstein’s
photoelectric equation
Stefan’s law
1
En = − 2
n
Doppler effect
λ=
h
h
=
p mv
de Broglie formula
θ≈
1.22 λ
d
Rayleigh criterion
energy level equation
 me e 4 
13.6
 2 2  = − 2 eV for hydrogen atom
n
8 ε o h 
HKDSE Physics Formulae P.3
(resolving power)