**Physics Optional IFoS Syllabus **

**Brief Information:****The UPSC(Union Public Service Commission) conducts the Indian Forest Service Examination along with UPSC Civil Service Examination (CSE). It is conducted every year. The Exam is has 3 Phase – Prelims, Mains and Interview. The Prelim is common for UPSC CSE and UPSC IFoS. The Syllabus for Physics Optional for IFos Mains is as given below:**

## Paper I

**Section-A**

**1. Classical Mechanics**

**(a) Particle dynamics:** Centre of mass and laboratory coordinates, conservation of linear and angular momentum, The rocket equation, Rutherford scattering, Galilean transformation, inertial and non-inertial frames, rotating frames, centrifugal and Coriolls forces, Foucault pendulum.

**(b) System of particles :** Constraints, degrees of freedom, generalised coordinates and momenta.Lagrange’s equation and applications to linear harmonic oscillator, simple pendulum and central force problems. Cyclic coordinates, Hamiltonian Lagrange’s equation from Hamilton’s principle.

**(c) Rigid body dynamics :** Eulerian angles, inertia tensor, principal moments of inertia. Euler’s equation of motion of a rigid body, force-free motion of a rigid body, Gyroscope.

**2. Special Relativity, Waves & Geometrical Optics :**

**(a) Special Relativity :** Michelson-Morley experiment and its implications, Lorentz transformationslength contraction, time dilation, addition of velocities, aberration and Doppler effect, mass energy relation, simple application to a decay process, Minkowski diagram, four dimensional momentum vector. Covariance of equations of physics.

**(b) Waves:** Simple harmonic motion, damped oscillation, forced oscillation and resonance, Beats, Stationary waves in a string. Pulses and wave packets. Phase and group velocities. Reflection and Refraction from Huygens’ principle.

**(c) Geometrical Optics :** Laws of reflection and refraction from Format’s principle. Matrix method in paraxial optic-thin-lens formula, nodal planes, system of two thin lenses, chromatic and spherical aberrations.

**3. Physical Optics :**

**(a) Interference :** Interference of light-Young’s experiment, Newton’s rings, interference by thin films, Michelson interferometer. Multiple beam interference and Fabry-Perot interferometer. Holography and simple applications.

**(b) Diffraction :** Fraunhofer diffraction-single slit, double slit, diffraction grating, resolving power. Fresnel diffraction:- half-period zones and zones plates. Fersnel integrals. Application of Cornu’s spiral to the analysis of diffraction at a straight edge and by a long narrow slit. Deffraction by a circular aperture and the Airy pattern.

**(c) Polarisation and Modern Optics :** Production and detection of linearly and circularly polarised light. Double refraction, quarter wave plate. Optical activity. Principles of fibre optics attenuation; pulse dispersion in step index and parabolic index fibres; material dispersion, single mode fibres.Lasers-Einstein A and B coefficients, Ruby and He-Ne lasers. Characteristics of laser light-spatial and temporal coherence. Focussing of laser beams. Three-level scheme for laser operation.

**Section-B**

**4. Electricity and Magnetism:**

**(a) Electrostatics and Magneto-statics :** Laplace and Poisson equations in electrostatics and their applications. Energy of a system of charges, multiple expansion of scalar potential. Method of images and its applications. Potential and field due to a dipole, force and torque on a dipole in an external field.Dielectrics, polarisation, Solutions to boundary-value problemsconducting and dielectric spheres in a uniform electric field. Magnetic shell, uniformly magnetised sphere.Ferromagnetic materials, hysteresis, energy loss.

**(b) Current Electricity:** Kirchhoff’s laws and their applications, Biot- Savart law, Ampere’s law, Faraday’s law, Lenz’ law. Self and mutual inductances. Mean and rms values in AC circuits, LR, CR and LCR circuits-series and parallel resonance, Quality factor, Principle of transformer.

**5. Electromagnetic Theory & Black Body Radiation :**

**(a) Electromagnetic Theory : **Displacement current and Maxwell’s equations. Wave equations in vacuum, Poynting theorem, Vector and scalar potentials, Gauge invariance, Lorentz and Coulomb gauges, Electromagnetic field tensor, covariance of Maxwell’s equations. Wave equations in isotropic dielectrics, reflection and refraction at the boundary of two dielectrics. Fresnel’s relations, Normal and anomalous dispersion, Rayleigh scattering.

**(b) Blackbody radiation:** Blackbody radiation ad Planck radiation law-Stefan-Boltzmann law, Wien displacement law and Rayleigh-Jeans law, Planck mass, Planck length, Planck time, Plank temperature and Planck energy.

**6. Thermal and Statistical Physics :**

**(a) Thermodynamics:** Laws of thermodynamics, reversible and irreversible processes, entropy, Isothermal, adiabatic, isobaric, isochoric processes and entropy change, Otto and Diesel engines, Gibbs’ phase rule and chemical potential. Van der Waals equation of state of real gas, critical constants. Maxwell-Boltzman distribution of molecular velocities, transport phenomena, equipartition and virial theorems, Dulong-Petit, Einstein, and Debye’s theories of specific heat of solids. Maxwell relations and applications. Clausius-Clapeyron equation. Adiabatic demagnetisation, Joule-Kelvin effect and liquefication of gases.

**(b) Statistical Physics:** Saha ionization formula, Bose-Einstein condensation, Thermodynamic behaviour of an ideal Fermi gas, Chandrasekhar limit, elementary ideas about neutron stars and pulsars, Brownian motion as a random walk, diffusion process. Concept of negative temperatures.

## Paper II

**Section-A**

**1. Quantum Mechanics I:** Wave-particle duality. Schroedinger equation and expectation values. Uncertainty principle, Solutions of the onedimensional Schroedinger equation free particle (Gaussian wave-packet), particle in a box, particle in a finite well, linear, harmonic oscillator, Reflection and transmission by a potential step and by a rectangular barrier, use of WKB formula for the life-time calculation in the alphadecay problem.

**2. Quantum Mechanics II & Atomic Physics :**

**(a) Quantum Mechanics II :** Particle in a three dimensional box, density of states, free electron theory of metals, The angular momentum problem, The hydrogen atom, The spin half problem and properties of Pauli spin matrices.

**(b) Atomic Physics :** Stern-Gerlack experiment, electron spin, fine structure of hydrogen atom, L-S coupling, J-J coupling, Spectroscopic notation of atomic states, Zeeman effect, Frank-Condon principle and applications.

**3. Molecular Physics :** Elementary theory of rotational, vibrational and electronic spectra of diatomic molecules, Raman effect and molecular structure, Laser Raman spectroscopy importance of neutral hydrogen atom, molecular hydrogen and molecular hydrogen ion in astronomy Fluorescence and Phos-phorescence, Elementary theory and applications of NMR. Elementary ideas about Lamb shift and its significance.

**Section-B**

**4. Nuclear Physics : **Basic nuclear properties-size, binding energy, angular momentum, parity,magnetic moment, Semi-empirical mass formula and applications, Mass parabolas, Ground state of deuteron magnetic moment and non-central forces, Meson theory of nuclear forces, Salient features of nuclear forces, Shell model of the nucleus-success and limitations, Violation of parity in beta decay, Gamma decay and internal conversion, Elementary ideas about Mossbauer spectroscopy, Q-value of nuclear reactions, Nuclear fission and fusion, energy production in stars, Nuclear reactors.

**5. Particle Physics & Solid State Physics:**

**(a) Particle Physics:** Classification of elementary particles and their interactions, Conservation laws, Quark structure of hadrons. Field quanta of electro-weak and strong interactions. Elementary ideas about Unification of Forces, Physics of neutrinos.

**(b) Solid State Physics : **Cubic crystal structure, Band theory of solids-conductors, insulators and semiconductors, Elements of superconductivity, Meissner effect, Joseph-son junctions and applications, Elementary ideas about high temperature superconductivity.

**6. Electronics:** Intrinsic and extrinsic semiconductors-pn- p and n-p-n transistors, Amplifiers and oscillators, Op-amps, FET, JFET and MOSFET, Digital electronics-Boolean identities, De-Morgan’s laws, Logic gates and truth tables, Simple logic circuits, Thermistors, solar cells, Fundamentals of microprocessors and digital computers.