Fundamentals of Physics
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| Discuss Fundamentals of Physics BASIC PHYSICS
UNITS
Physics, as a subject deals with the laws of nature, this study is quantitative and requires the measurement and comparison of physical quantities. In order to solve this problem we use standard units. A unit is nothing but a specified measure of a physical quantity, such as length, area, volume, mass, time etc. which are used to express the magnitude of that physical quantity.
SOME FUNDAMENTAL AND BASE QUANTITIES
|
QUANTITY |
NAME OF THE UNIT |
SYMBOL |
|
Length |
Metre |
m |
|
Mass |
kilogram |
kg |
|
Time |
second |
s |
|
Electric current |
ampere |
A |
|
Temperature |
kelvin |
K |
|
Amount of a substance |
mole |
Mol |
|
Luminous intensity |
candela |
cd |
DIMENSIONS
Dimensions are defined as the product or quotient of the basic physical quantities, raised to the appropriate powers, in a derived physical quantity. These basic physical quantities in physics consists of mass (M), length (L) and time (T).
UNITS AND DIMENSIONS OF SOME PHYSICAL QUANTITIES
|
PHYSICAL QUANTITY |
DENOTED BY |
STANDARD INTERNATIONAL(SI) UNIT |
DIMENSION |
|
Displacement |
s |
Metre (m) |
L (basic) |
|
Area |
A |
m2 |
L2 |
|
Volume |
V |
m3 |
L3 |
|
Mass |
M, m |
Kilogram (kg) |
M (basic) |
|
Time |
t |
Second (s) |
T (basic) |
|
Density |
r |
Kg/m3 |
M/L3 |
|
Velocity |
v, u |
m/s |
L/T |
|
Acceleration |
a |
m/s2 |
L/T2 |
|
Force |
F |
Newton (N) |
ML/T2 |
|
Work |
W |
Joule (J) =N-m |
ML2/T2 |
|
Energy |
E, U, K |
Joule (J) |
ML2/T2 |
|
Power |
P |
Watt (W)=J/s |
ML2/T3 |
|
Momentum |
p |
Kg-m/s |
ML/T |
|
Gravitational constant |
G |
N-m2/kg2 |
L3/MT2 |
|
Angle |
q, j |
radian |
|
|
Angular velocity |
w |
radian/s |
T-1 |
|
Angular acceleration |
a |
Radian/s2 |
T-2 |
|
Angular momentum |
L |
kg-m2/s |
ML2/T |
|
Moment of inertia |
I |
kg-m2 |
ML2 |
|
Torque |
t |
N-m |
ML2/T2 |
|
Angular frequency |
w |
radian/s |
T-1 |
|
Frequency |
n |
Hertz (Hz) |
T-1 |
|
Period |
T |
s |
T |
|
Young’s Modulus |
Y |
N/m2 |
M/LT2 |
|
Bulk modulus |
B |
N/m2 |
M/LT2 |
|
Shear modulus |
h |
N/m2 |
M/LT2 |
|
Surface tension |
S |
N/m |
M/LT |
|
Coefficient of viscosity |
h |
N-s/M2 |
M/LT |
|
Pressure |
P, p |
Pascal (pa), N/M2 |
M/LT2 |
|
Wavelength |
l |
m |
L |
|
Wave intensity |
I |
W/m2 |
M/T3 |
|
Temperature |
T |
Kelvin (K) |
K (basic) |
|
Specific heat capacity |
c |
J/kg-K |
L2/T2K |
|
Stefan’s constant |
s |
W/m2-K4 |
M/T3K4 |
|
Heat |
Q |
J |
ML2/T2 |
|
Thermal conductivity |
K |
W/m-K |
ML/T3K |
|
Current |
I |
Ampere |
I (basic) |
|
Current density |
s |
Mho/m |
I2T3/ML3 |
|
Electric dipole moment |
p |
C-m |
LIT |
|
Electric Field |
E |
V/m |
ML/IT3 |
|
Potential difference |
V |
Volt (V) = J/C |
ML2/IT3 |
|
Electric flux |
F |
V-m |
ML3/IT3 |
|
Capacitance |
C |
Farad (F) |
I2T4/ML2 |
|
Electromotive force |
e |
Volt (V) |
ML2/IT3 |
|
Resistance |
R |
Ohm |
ML2/I2T3 |
|
Permittivity of Space |
e0 |
C2/N-m2 |
I2T4/ML3 |
|
Permeability of Space |
m0 |
N/A2 |
ML/I2T3 |
|
Magnetic field |
B |
Tesla (T) |
M/IT2 |
|
Magnetic flux |
FB |
Weber (Wb) |
ML2/IT2 |
|
Magnetic dipole moment |
m |
N-m/T |
IL2 |
|
Inductance |
L |
Henry (H) |
ML2/I2T2 |