Formatting page ...
Physics Formula guide for ICSE standard 10 Contents How to solve a problem in Physics ......................................................................................................... 2 Page | 1 Important terms and their units ............................................................................................................. 2 Chapter 1 Force ....................................................................................................................................... 3 1.1 Formula Quick reference: Force ................................................................................................... 3 Chapter 2 Work Power and Energy......................................................................................................... 3 2.1 Formula quick reference: Work power and Energy ...................................................................... 3 Chapter 3 Machines ................................................................................................................................ 5 3.1 Formula and quick reference card: ............................................................................................... 5 3.2 Inclined plane and gear ................................................................................................................. 6 Pulley................................................................................................................................................... 7 Chapter 4 Refraction of Light .................................................................................................................. 8 Refraction of Light through a prism .................................................................................................... 8 Chapter 5 Refraction of Light through a Lens ......................................................................................... 9 Chapter 7 Sound ..................................................................................................................................... 9 Chapter 8 Current electricity ................................................................................................................ 10 8.1 Formula and quick reference card: ............................................................................................. 10 8.2 Electro-Motive force, Terminal voltage and internal resistance of a cell ................................... 11 Chapter 9 Electrical Power and Household Circuits ............................................................................. 12 Chapter 9 Calorimetry........................................................................................................................... 12 Author Srikanth K S All rights reserved Page 1 Physics Formula guide for ICSE standard 10 How to solve a problem in Physics Page | 2 1. 2. 3. 4. 5. 6. 7. Read the problem at least twice Write down what is given in the problem Draw a diagram Ensure to draw the direction in case of ray diagrams and different forces. Write down the formulae that will help you to solve the problem Solve the problem by proper substitution. Simplify your answer Don t forget to write the units Important terms and their units Term Length Mass Time Force Force SI unit to CGS unit conversion Velocity Acceleration Moment of force Moment of force Remember Energy of sub atomic particles Description Meters Kilo gram Seconds Newton , CGS unit Dyne 1N = 105 dynes Meters per second Meters per second squared In SI Units its Newton meter In CGS Units its dyne centimeter 1Nm = 107 dyne cm 1kgf X m = 9.8Nm 1gf X cm = 980 dyne cm 1 joule = 1 newton X 1 meter 1 Joule = 107 erg 1 Joule/ second 1 W = 1 Js-1 = 107 erg s-1 1 HP = 746 W = 0.746 kW 1 joule = 1 newton X 1 meter Electrical Energy is expressed as Kilowatt hour 1eV = 1.6 X 10-19 J Machines Wavelength Frequency Current Voltage Resistance Mechanical advantage, Velocity ratio Symbol Hertz Amphers Volts Ohms Work Remember Power Remember Energy Author Srikanth K S All rights reserved SI Unit m Kg s N m/s m/s2 Nm dyne cm Joule Watt Joule Electron volt (eV) Unit less m Hz A V Page 2 Physics Formula guide for ICSE standard 10 Chapter 1 Force 1.1 Formula Quick reference: Force Newton s second law Force is directly proportional to the rate of change of momentum and indirectly proportional to rate of change of time Momentum is the product of mass and velocity Page | 3 Momentum Change in momentum Rate of change of momentum Rate of change of momentum ( ) Force = Mass X Acceleration 1 N = 105 Dynes Newton is the SI unit and Dyne is CGS Unit Gravitational unit of force Equation of motion 1Nm = 107 dynes cm 1kgf X m = 9.8 Nm 1 gf X cm = 980 dyne cm Principle of moments Sum Clock wise moments = Sum anti clockwise moments Chapter 2 Work Power and Energy 2.1 Formula quick reference: Work power and Energy Work Work done = Force X Displacement When the work done by the force when the displacement is not along the force When , example Positive work done by a force of gravity in free fall Work Positive Work Zero work done Negative work done , when Work done when a coolie is carrying some load on his head moves horizontally. Note : Zero work done by centripetal force. Work done is ve when Example when a ball is thrown up in the air. Work done by force of Author Srikanth K S All rights reserved Page 3 Physics Formula guide for ICSE standard 10 gravity Unit of work CGS Unit of work Conversion of Joules to Page | 4 ergs Power Unit of power = 1 joule = 1 N * 1 m Kilo joules = 1000 Joules 1 erg = 1dyne x 1cm 1 Joule = 107 erg 1N = 105 dyne and 1m = 102 cm 105 X 102 =107 erg The rate of doing work is called power Power is also the product of force and average speed SI Unit of power is Watts -1 -1 Conversion of SI unit to CGS Units Energy Unit of energy Heat energy = 107 ergs -1 1 HP = 746 W = 0.746 kW The energy of a body is the ability to do work -1 X 3600 s = 3.6kJ 1 Kilowatt hour = 3.6 X 106 J Heat energy is usually measured in calorie. 1 Calorie of heat energy required to raise the temperature of 1g of water from 14.5o C to 15.5o C Relationship of Calorie and Joule Electron volt Kinetic energy Measurement of kinetic energy Relationship between momentum and kinetic energy Work energy theorem Author Srikanth K S All rights reserved The Energy of atomic particle is very small. It is measured in terms of electron volt (eV) 1eV = 1.6 X 10-19 J Different forms of energy The energy processed by a body by virtue of its state of motion The kinetic energy possessed by a moving body can be measured as the amount of work which the moving body can perform before it comes to rest 2 2 ( ) Work done by a force on a moving body is equal to the increase in kinetic energy. Page 4 Physics Formula guide for ICSE standard 10 Proof On Simplification Page | 5 ( ( Types of Kinetic energy ) ) ( ) Translational kinetic energy Rotational kinetic energy Vibrational kinetic energy Potential energy Forms of potential energy Car moving in a straight path Free falling object Spinning top Movement to and fro from a mean position example plucking a guitar string Energy possessed by a body at rest Mechanical potential energy 1. Gravitational potential energy 2. Elastic potential energy Gravitational potential energy Energy degradation Law of conservation of energy Conservation of energy and energy degradation The gradual decrease of useful energy due to radiation loss, frictional loss etc is called degradation of energy Energy can neither be created or destroyed Chapter 3 Machines 3.1 Formula and quick reference card: Load Effort Mechanical Advantage Mechanical Advantage MA The resistive or opposive force to be overcome by a machine is called load The force applied on the machine to overcome the load is called Effort Ratio of Load to effort ( ) ( ) MA = Velocity Ratio VR VR = Velocity of Load VL = Velocity of Effort VE = Author Srikanth K S All rights reserved The ratio of the velocity of effort to the velocity of load dL is the distance moved by the Load in time t dE is the distance moved by Page 5 Physics Formula guide for ICSE standard 10 Velocity Ratio VR VR = Work input The work done on the machine by the effort The work done by the machine on the load The ratio of the useful work done by the machine to the work put into the machine by the effort A machine in which there is no loss of energy in any manner An actual machine has an efficiency always less than 100% because the moving parts are neither weightless or frictionless Strings are not perfectly elastic and the different parts are not rigid MA = VR X Page | 6 Work Output Efficiency ( ) Ideal machine Actual Machine Relationship between efficiency mechanical advantage and velocity ratio Class 1 Lever Class 2 Lever Class 3 Lever the Effort in time t Note velocity ratio has no unit as it s a ratio Efficiency ( ) = The efficiency of an ideal machine is 100% Fulcrum is in between the effort and load Effort and Load are in the same direction MA can be <1 = 1 or >1 See Saw, Plier, crow bar, scissors Mechanical advantage of the lever is always > 1 Effort is in between the fulcrum and the load MA is always < 1 Bottle opener, Nut cracker Sugar tongs, Knife spade 3.2 Inclined plane and gear Inclined plane Author Srikanth K S All rights reserved A sloping surface that behaves like a simple machine whose MA is always greater than 1 Page 6 Physics Formula guide for ICSE standard 10 MA and VR of an inclined plane VR = MA = This is true in the absence of friction Gear A wheel with teeth around its rim Gear Ratio Gear Ratio = Where Na is the number of teeth in the driving and Nb is the number of teeth in the driven Page | 7 Relationship between number of teeth, radius and the speed of rotation = = Pulley Single Fixed Pulley A pulley which has its axis of rotation fixed in position is called fixed pulley MA = Single Movable pulley A pulley whose axis of rotation is not fixed in position is called a movable pulley. It is also called as a force multiplier MA = Author Srikanth K S All rights reserved = =1 = =2 Page 7 Physics Formula guide for ICSE standard 10 Combination Pulleys One fixed and other movable Pulley s MA =VR = 2n Block and Tackle pulley MA = Page | 8 VR = = =n =n Chapter 4 Refraction of Light Refraction of Light Change in direction of the path of light when it passes from one transparent medium to another transparent medium Refractive Index = = Snells law Refraction of Light through a prism Prism Author Srikanth K S All rights reserved A transparent refracting medium bounded by 5 surface inclined at the same angle Page 8 Physics Formula guide for ICSE standard 10 Page | 9 Chapter 5 Refraction of Light through a Lens Lens Convex lens or converging lens Concave Lens A transparent refracting medium bounded by two curved surface which are generally spherical Thicker in the middle and thinner in the periphery Thicker in the periphery and thinner in the middle Chapter 7 Sound Longitudinal waves Author Srikanth K S All rights reserved The vibration of the medium is along the direction of propagation Page 9 Physics Formula guide for ICSE standard 10 Transverse wave Echo Page | 10 They can travel in solids liquids or gases The vibration of the medium is perpendicular to the direction of propagation They can only travel in solids or liquids The sound heard after reflection from a distant obstacle after the original sound has ceased is called an echo. An echo is heard only if the distance between the person producing the sound and the rigid obstacle is long enough to allow the reflected sound to reach the person at least 0.1 second later Distance D= Relations between velocity and frequency Frequency of vibration V=f f= ( ) Chapter 8 Current electricity 8.1 Formula and quick reference card: Current Rate of flow of charge Unit of current -1 Ampere Coulomb If n electrons pass through a cross section of a conductor in time t, then the total charge passed through the conductor is given as Unit of charge Flow of current Potential Potential at a point Direction of flow of charge when two conductors are placed in contact. It is the amount of work done in bringing a unit positive charge from infinity to that point Potential at a point - Unit is volts 1 Potential difference Resistance and its relation with length and area of cross section Ohms law Author Srikanth K S All rights reserved Pd between two points is the work done in moving a unit positive charge from one point to the other Current flowing in a conductor is directly proportional to the potential difference across its ends provided Page 10 Physics Formula guide for ICSE standard 10 the physical conditions and the temperature of the conductor remain constant Specific resistance or resistivity Page | 11 Where is the specific resistance 8.2 Electro-Motive force, Terminal voltage and internal resistance of a cell Electro motive force (EMF) When no current is drawn from a cell that is the cell is open, the potential difference between the terminal o the cell is called electro motive force ( ) The EMF of a cell is defined as the energy spent per unit charge in taking a positive charge around the complete circuit Terminal voltage of a cell = Voltage drop in a cell Representation of a cell with internal resistance = V +v or V = - v Resistors in series Effective resistance R = R1 + R2 + .. Rn Author Srikanth K S All rights reserved When current is drawn from a cell when the cell is In closed circuit. The potential difference between the electrodes is called terminal voltage V= Page 11 Physics Formula guide for ICSE standard 10 Resistors in Parallel Effective resistance Formula = + + + . Page | 12 Chapter 9 Electrical Power and Household Circuits Electrical Energy Charge Electrical Power Commercial unit of electrical energy Remember Remember W = Q V or W = VI t or W = I2Rt or V2t/R Q = I X t Columb P = VI or I2R or V2/R or W/t W = power X time 1 Wh = 3600 Joules Fuse is made up of an alloy of Lead and Tin A bulb (incandescent lamp) filament is made up of tungsten Unit Joules Unit Watt Unit Watt second Chapter 10 Calorimetry Heat Temperature of a substance One calorie One Kilo calorie Heat capacity The kinetic energy due to random motion of molecules of a substance. The average internal kinetic energy of molecules of a substance One calorie of heat is the heat energy required to raise the temperature of 1g of water from 14.50C to 15.50C One Kilo calorie of heat is the heat energy required to raise the temperature of 1Kg of water from 14.50C to 15.50C The heat capacity of a body is the amount of heat energy required to raise its temperature by 10c or 1K Specific heat capacity c= Principle of calorimetry Melting C= Heat energy lost by A is equal to the heat energy gained by B m1c1 (t1 t) = m2 c2 (t t2) Change of state from solid to liquid. The temperature at which this state change happens is called melting point Change of state from liquid to gas. The temperature at which this state change happens is called boiling point Boiling Author Srikanth K S All rights reserved Joules/ kelvin Page 12
|
