Units and Formulas by ICSEHUB
(based on ICSE class-10 Syllabus)
|
FORCE |
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|
Concept |
Formula |
S.I. |
CGS |
|
Force |
m x a |
Newton (N) |
dyne (10-5
N) |
|
Torque |
F
x ( ⊥ distance between Point of action and axis) |
Newton-meter |
dyne-cm |
|
Work , Energy and Power |
|||
|
Concept |
Formula |
S.I. |
CGS |
|
Work |
Force x
Displacement x cosθ M x g x h Change in Kinetic
Energy |
Joule (J) |
erg (10-7 J) |
|
Power |
Work
/ Time |
Watt
(W) |
erg
/ sec |
|
Commercial Energy |
Power X Time |
Watt-hour &
KiloWatt-hour |
|
|
Energy |
Kinetic : ½
mv2 Potential
: mgh |
Joule
(J) |
erg
(10-7 J) |
|
Electron Volt |
Charge of 1
electron x 1V |
1.6 x 10-19J |
Not required |
|
Machines |
|
|
Concept |
Formula |
|
Mechanical Advantage (M.A) |
Load/Effort Effort Arm / Load
Arm |
|
Velocity Ratio (V.R.) |
Effort
Velocity / Load Velocity Effort
Distance / Load Distance |
|
Efficiency |
(Work Output /
Work Input) M.A / V.R |
1 Horsepower = 746 Watt
Mechanical Energy = K.E. + P.E.
MA and VR have no units as they are
ratios.
|
Light and Sound |
|
|
Concept |
Formula |
|
Frequency |
1/ Time Period (Hertz) |
|
Speed of light in a medium |
Wavelengh
x Frequency Wavelength
/ Time period |
|
Refractive Index |
sin i / sin r Speed of light in
vaccume / Speed of
light in other medium Real depth / Apparent depth 1 / sin c ; c = (critical angle) |
|
Lens Formula |
1/f
= 1/v 1/u v = image
distance u = object distance Very Important || v
- image Oh U(you)
|| Object u |
|
Magnification |
Height of Image / Height of Object Image
distance / Object distance |
|
Power |
1
/ focal length of
lens in meters SI unit : Dioptre (D) Covenx +D , Concave D |
|
Magnifing Power |
1 + 0.25 / focal
length Unit
: Dioptre |
|
Speed of Sound |
2
x Distance / Time Taken |
|
Electricity |
||
|
Concept |
Formula |
Unit |
|
Current |
Charge /
Time (Q/t) |
Ampere |
|
Potentital Difference |
V
= Current x Resistance V
= IR V
= Emf - v |
Volt |
|
Resistance (R) |
Potential
Difference / Current Resistivity x
Length / Cross-section Area |
Ohm |
|
Emf |
Current
x Total Resistance Terminal
Voltage + Voltage Drop |
Volt |
|
Internal Resistance (r) |
# r = ( Emf/V - 1)R |
Ohm |
|
Total Resistance |
R
+ r |
Ohm |
|
Resistivity |
R x a/L |
Ohm-meter |
|
Voltage Drop (v) |
Current
x Internal Resistance |
Volt |
|
Conductance |
1 / Resistance |
Mho |
|
Conductivity |
1
/ Resistivity |
1
/ ohm x meter |
|
Connection Resistance |
Series
: R = r1 + r2 +
r3
. Parallel
:1/R = 1/r1 + 1/r2 + 1/r3 |
Ohm |
|
Household Circuits |
||
|
Concept |
Formula |
Unit |
|
Electric Work (W) |
VIt I2Rt |
Joule |
|
Power (P) |
V
x I W/t |
Watt |
|
Heat (H) |
I2Rt |
Joule |
|
Electromagnetism |
||
|
Concept |
Formula |
Unit |
|
Force |
iBL |
Newton |
|
Magnetic Strength (B) |
F
/ IL |
Tesla |
|
Heat (H) |
I2Rt |
Calorie or Joule |
EXAMINERS SUGESTIONS (Issued by Council)
a)
Avoid
selective study.
b)
Read
the questions heedfully and write answer in brief and to the point.
c)
Express
the answer only in SI units unless otherwise asked.
d)
Learn
the principles, laws and definitions accurately.
e)
Focus
more on conceptual learning rather than the rote learning.
f)
Make
observations and try to relate your learning with it.
g)
State
the meaning of the symbols if the answer is given in terms of any
formula/mathematical equation.
h)
Use
abbreviations/symbols which are standard/acceptable.
i)
Solve
at least the last five years I.C.S.E. question papers.
j)
Write
in a neat and legible handwriting.
k)
Avoid
changing the order of sequence of questions and numbering system while
attempting the paper.
l)
Express
final answer with proper unit as per the requirement of the question.
m) While writing the answers it is not only
important to cover all the points but also to present them in a proper
sequence.
n)
It is
better to inculcate the habit of underlining the important points or key words
in the answer.