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### Lecture 3: Electricity Part-3

00:18:44

Published    09-Oct-2018      Bilingual

## COMPLETE COURSE PHYSICS COMPETITIVE EXAM NDA

Study Khazana delivers Competitive Exam NDA, fifty two video lectures by Akash Sehwag on Physics Complete Course with complete solutions using sample paper based on Syllabus. This chapter covers the following topic to make students understand the topic and covers the whole chapter with all the question and answers

## WHAT WE STUDY IN ELECTRICITY?

• Define Electric current and potential difference
• Explain Ohm's law
• Definition of Resistance and Resistivity,
• Discus the Factors on which the resistance of a conductor depends
• What is Series combination of resistors, parallel combination of resistors and its applications in daily life?
• Describe Heating effect of electric current and its applications in daily life
• Explain Electric power, Inter relation between P, V, I and R.

## WHAT WE STUDY IN KINEMATICS?

·
• Frame of reference
• Motion in a straight line
• Position-time graph
• Speed and velocity
• Elementary concepts of differentiation and integration for describing motion
• Uniform and non-uniform motion ·
• Average speed and instantaneous velocity
• Uniformly accelerated motion
• Velocity time
• Position-time graphs
• Relations for uniformly accelerated motion (graphical treatment)
• Scalar and vector quantities
• Position and displacement vectors
• general vectors and their notations
• equality of vectors, multiplication of vectors by a real number
• addition and subtraction of vectors
• Relative velocity
• Unit vector
• Resolution of a vector in a plane - rectangular components
• Scalar and Vector product of vectors
• Motion in a plane
• Cases of uniform velocity and uniform acceleration-projectile motion
• Uniform circular motion

## WHAT WE STUDY IN WORK, ENERGY AND POWER?

• Work done by a constant force and a variable force
• Kinetic energy
• Work-energy theorem
• Power
• Notion of potential energy
• Potential energy of a spring
• Conservative forces
• Conservation of mechanical energy (kinetic and potential energies)
• Non-conservative forces
• Motion in a vertical circle
• Elastic and inelastic collisions in one and two dimensions

## WHAT WE STUDY IN LAW OF MOTION?

• Intuitive concept of force
• Inertia
• Newton's first law of motion
• momentum and Newton's second law of motion
• impulse; Newton's third law of motion
• Law of conservation of linear momentum and its applications
• Equilibrium of concurrent forces
• Static and kinetic friction
• laws of friction
• rolling friction
• lubrication
• Dynamics of uniform circular motion:

## WHAT WE STUDY IN GRAVITATION?

• Keplar's laws of planetary motion
• The universal law of gravitation
• Acceleration due to gravity and its variation with altitude and depth
• Gravitational potential energy and gravitational potential
• Escape velocity
• Orbital velocity of a satellite
• Geo-stationary satellites

## WHAT WE STUDY IN ROTATIONAL MOTION?

• Centre of mass of a two-particle system
• momentum conservation and centre of mass motion
• Centre of mass of a rigid body
• Centre of mass of a uniform rod
• Moment of a force
• Torque
• angular momentum
• laws of conservation of angular momentum and its applications
• Equilibrium of rigid bodies
• rigid body rotation and equations of rotational motion
• comparison of linear and rotational motions
• Moment of inertia
• Values of moments of inertia, for simple geometrical objects (no derivation)
• Statement of parallel and perpendicular axes theorems and their applications

## WHAT WE STUDY IN MECHANICAL PROPERTIES OF FLUIDS?

• Pascal's law and its applications (hydraulic lift and hydraulic brakes)
• Effect of gravity on fluid pressure
• Viscosity
• Stokes' law
• terminal velocity
• streamline and turbulent flow
• critical velocity
• Bernoulli's theorem and its applications
• Surface energy and surface tension
• angle of contact
• excess of pressure across a curved surface
• application of surface tension ideas to drops
• bubbles and capillary rise

## WHAT WE STUDY IN THERMODYNAMICS?

·        Thermal equilibrium and definition of temperature
• Zeroth law of thermodynamics
• Heat, work and internal energy
• First law of thermodynamics
• Second law of thermodynamics −
• Reversible and irreversible processes
• Heat engine and refrigerator

## WHAT WE STUDY IN WAVES?

·        Wave motion
• Transverse and longitudinal waves
• speed of wave motion
• Displacement relation for a progressive wave
• Principle of superposition of waves
• reflection of waves
• standing waves in strings and organ pipes
• fundamental mode and harmonics
• Beats
• Doppler effect

## WHAT WE STUDY IN CURRENT ELECTRICITY?

• Electric current, flow of electric charges in a metallic conductor, drift velocity, mobility and their relation with electric current
• Ohm’s law, electrical resistance, V-I characteristics (linear and non-linear), electrical energy and power, electrical resistivity and conductivity
• Carbon resistors, colour code for carbon resistors; series and parallel combinations of resistors; temperature dependence of resistance
• Internal resistance of a cell, potential difference and EMF of a cell, combination of cells in series and in parallel
• Kirchhoff’s laws and simple applications
• Wheatstone bridge, metre bridge
• Potentiometer − o   Principle and its applications to measure potential difference and for comparing EMF of two cells o   Measurement of internal resistance of a cell

## WHAT WE STUDY IN MOVING CHARGES AND MAGNETISM?

• Concept of magnetic field − o   Oersted’s experiment
• Biot - Savart law and its application to current carrying circular loop
• Ampere’s law and its applications to infinitely long straight wire
• Straight and toroidal solenoids
• Force on a moving charge in uniform magnetic and electric fields
• Cyclotron
• Force on a current-carrying conductor in a uniform magnetic field
• Force between two parallel current-carrying conductors-definition of ampere
• Torque experienced by a current loop in uniform magnetic field; moving coil galvanometer-its current sensitivity and conversion to ammeter and voltmeter.

## WHAT WE STUDY IN MAGNETISM AND MATTER?

• Current loop as a magnetic dipole and its magnetic dipole moment
• Magnetic dipole moment of a revolving electron
• Magnetic field intensity due to a magnetic dipole (bar magnet) along its axis and perpendicular to its axis
• Torque on a magnetic dipole (bar magnet) in a uniform magnetic field − o   Bar magnet as an equivalent solenoid o   Magnetic field lines o   Earth’s magnetic field o   Magnetic elements
• Para-, dia- and ferro - magnetic substances, with examples
• Electromagnets and factors affecting their strengths
• Permanent magnets

## WHAT WE STUDY IN RAY OPTICS AND OPTICAL INSTRUMENTS?

• Ray Optics − o   Reflection of light o   Spherical mirrors o   Mirror formula o   Refraction of light o   Total internal reflection and its applications o   Optical fibres o   Refraction at spherical surfaces o   Lenses o   Thin lens formula o   Lensmaker’s formula
• Magnification, power of a lens, combination of thin lenses in contact combination of a lens and a mirror
• Refraction and dispersion of light through a prism.
• Scattering of light - blue colour of sky and reddish appearance of the sun at sunrise and sunset
• Optical instruments: Microscopes and astronomical telescopes (reflecting and refracting) and their magnifying powers

## WHAT WE STUDY IN WAVE OPTICS?

• Wave optics: Wave front and Huygen's principle, reflection and refraction of plane wave at a plane surface using wave fronts
• Proof of laws of reflection and refraction using Huygen's principle
• Interference Young's double slit experiment and expression for fringe width, coherent sources and sustained interference of light
• Diffraction due to a single slit, width of central maximum
• Resolving power of microscopes and astronomical telescopes
• Polarisation, plane polarised light Brewster's law, uses of plane polarised light and Polaroids

## WHAT WE STUDY IN DUAL NATURE OF RADIATION AND MATTER?

• Photoelectric effect
• Hertz and Lenard’s observations
• Einstein’s photoelectric equation-particle nature of light
• Matter waves-wave nature of particles, de Broglie relation
• Davisson-Germer experiment (experimental details should be omitted; only conclusion should be explained).

## WHAT WE STUDY IN ATOMS?

• Alpha-particle scattering experiment
• Rutherford’s model of atom
• Bohr model
• Energy levels
• Hydrogen spectrum

## WHAT WE STUDY IN NUCLEI?

• Composition and size of −
• Nucleus
• Atomic masses
• Isotopes
• Isobars
• Isotones
• Radioactivity alpha, beta and gamma particles/rays and their properties
• Mass-energy relation −
• Mass defect
• Binding energy per nucleon and its variation with mass number
• Nuclear fission
• Nuclear fusion

## HOW WE HELP THE STUDENTS?

These video lectures will make the subject easy for students. The free lecture is available as a demo. We provide mock exams after completion of the full course. These lectures are recording of the live session taken. It will include question and answers of the students undertaken during the class NDA previous question papers and sample papers are also given to the students for practice. Video Lectures classes are taken by Study Khazana’s best faculties. Video lectures contain examples and formulas related to different topics. We have doubt sessions on YouTube related to students queries asked on WhatsApp. These classes are based on Syllabus. We offer pen drives and online-offline study mode to the students. We also have Android and IOS Study Khazana mobile app for helping students to study anywhere at any time.

#### Akash Sehwag

 Phone: 99********38 Email: aka********@gmail.com Address: Institute: