Mechanics:

  • Newton's Second Law: F = ma
  • Work-Energy Theorem: W = ΔKE = Fd
  • Kinetic Energy: KE = 1/2mv^2
  • Potential Energy: PE = mgh
  • Law of Conservation of Energy: KEi + PEi = KEf + PEf
  • Hooke's Law: F = -kx
  • Simple Harmonic Motion: x(t) = A cos(ωt + φ)
  • Newton's Law of Universal Gravitation: F = Gm1m2/r^2

Waves:

  • Wave Equation: v = λf
  • Wave Speed: v = d/t
  • Periodic Wave Equation: y(x,t) = A sin(kx ± ωt)
  • Amplitude: A = max displacement from equilibrium
  • Wavelength: λ = distance between successive peaks/troughs
  • Frequency: f = number of cycles per second (Hz)
  • Phase Velocity: vph = ω/k
  • Intensity: I = P/A (power per unit area)

Thermal Physics:

  • Specific Heat: Q = mcΔT
  • Ideal Gas Law: PV = nRT
  • Heat Transfer: Q/t = kA(T1 - T2)/d
  • Thermal Expansion: ΔL = αLΔT
  • First Law of Thermodynamics: ΔU = Q - W
  • Efficiency: η = W/Qh
  • Entropy: ΔS = Q/T

Gravitational Fields:

  • Newton's Law of Universal Gravitation: F = Gm1m2/r^2
  • Gravitational Potential Energy: U = -Gm1m2/r
  • Gravitational Field: g = F/m
  • Gravitational Field Intensity: g = Gm/r^2
  • Escape Velocity: v = sqrt(2GM/r)

Electric Fields:

  • Coulomb's Law: F = kq1q2/r^2
  • Electric Field Intensity: E = F/q
  • Electric Potential Energy: U = kq1q2/r
  • Electric Potential: V = U/q
  • Capacitance: C = Q/V
  • Capacitor Energy: U = 1/2CV^2

 

 

Hope this little summery will help you to go through the exercises. Practice is the key to success, so always practice and make these equations familiar. By understanding the core concepts behind these, you will be able to solve any Past paper question related to the unit matter and radiation.  

 

1) Black body radiation 

Stefan's Law 

Rate of energy emission (P) by a perfect black body, when its' temperature is (T), surface area (A).

- Stefan's constant (5.67 x 10 -8 Wm -2K -4)

Stefan's law

When above equation is applied for real objects, another constant (e)-Surface emmisivity, is added to the above equation. (e) depends on color and surface nature of the object. For perfect black bodies the value of (e) is 1.

Stefan's law for real objects

 

When an object is placed in an environment, heat exchange occurs between object and environment. Object obtains heat at the same time it is loosing heat. The net effect determine either object getting hotter or colder. 

Net power emission from an object with temperature (T), surface area (A) placed in an environment of temperature (T0 ), when surface emmisivity is (e), is given by;

Stefan's law, Net power emmission


 

  2) Photoelectric effect

Energy of a single photon of light (E), when (h)- Planck's constant(6.62607004 × 10-34 m2 kg / s) and (f)-Frequency

When a ray of frequency (f) greater than threshold frequency, incident on a metal surface. (Φ
)-Work function of the metal,(h)-Planck's constant, (KE)- kinetic energy of released electrons.

Φ- Work-function, h -Planck's constant, f0 -threshold frequency,


Vs - Stopping potential, KE -Maximum kinetic energy of released electrons, e -Charge of an electron.


 

3) Wave particle duality

λ -De Broglie wavelength, h-  Planck's constant, p- momentum 



4) Radioactivity 

A- Activity (Measured in ,Bq, becquerel), λ -disintegration constant, N -Number of radioactive nuclei. 


(N) number of radioactive nuclei in a sample after (t) time when initial number of radioactive nuclei was  (N0). (e)- Exponential constant. 


T1/2 -Half life (Time taken to halve the number of radioactive nuclei from an initial amount)

The End.