Units and Formulas by ICSEHUB

(based on ICSE class-10 Syllabus)

 FORCE 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

EXAMINERS 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.