The Science

Reflection of light (Optics)  :-   •Reflection :- The phenomenon in which the light traveling in a medium ,when made incident on the surface of another medium goes back in the same medium is called reflection . •Law of reflection :- The following experiments observation are called laws of reflection.  1. The incident ray, the normal to reflecting surface at the point of incident and reflected ray all lie in same plane.  2. The angle of incidence(i) is always equal to angle of reflection (r).               i=r •Some definitions:- • Incident Ray:- The incident light ray is a narrow light beam which is represented by a straight line, it intersects with the reflecting surface at the point of incidence. • Reflected Ray:- The reflected light ray is a narrow light beam which is represented by a straight line that is reflected from the reflected surface at the point of incidence. ...

Electromagnetic waves :- An electromagnetic wave is one in  which electric and magnetic field mutually perpendicular to each other as well as the direction of propagation of the wave. An accelerated charge produces a sinusoidal time varying magnetic field, which in turm produces a sinusoidal time electric field. The two fields so produced are mutually perpendicular and are source of each  other. The mutually perpendicular time using electric field and magnetic field constitute a electromagnetic waves which propagate in space in direction perpendicular to the direction of both the fields. Thus the electromagnetic waves consist of sinusoidal time varying electric and -ve field acting at right angle to each other as well as at right angle to the direction of propagation of waves as shown in figure. • Characterstics of electromagnetic waves :- 1. The electromagnetic waves are produced by an accelerated charge.  2.At any point in vacuum, the electric fiel...

Alternating current generator   (Electromagnetic induction and current) :- The device which converts mechanical energy into electrical energy is called alternating current generator.  • Principal :-  When magnetic flux linked with a coil changes, an induced e m f is produced across it.  • Construction :- It is consist of following four parts.  1.Armature :-  Armature ABCD ( also called coil)  consist of a large number of turns of insulate copper wire around over a soft iron core. It revolves round an axle between the two poles of a strong magnet . 2. field Magnet :-  It is usually a strong permanent magnet. The armature is rotated between the two poles of a strong magnet so that axis of the armature is perpendicular to magnetic field lines . 3. Slip rings :--- The leads from the arms of the armature are connected to the two rings R1 and R2  Respectively. These rings help to provide...

Eddy currents:-        The current induced in a conductor (metal sheet or metal block)  in form of clesed loops .these loops are called eddy currents because these currents look like Eddies or which pods. These current are also known as focarlt current.  Experiments :-   https://instagram.com/sachin_dreamboy?igshid=1647004f4d5r6 Explanation :- When the circuit is suritered  in, the current shorts growing through the solenoid. As the current grows, the magnetic field lines along the axis of the solenoid and hence the magnetic flux through the dix also increases from zero yo some finite value. Due to this, induced current are produced in the disc and the disc is converted into a small magnet. If the upper face of the soft iron core acquires N polarity in accordance with lenz's lawer face of the disc acquires N polarity due to repulsion face between the upper face of the soft iron core and the lower face of the disc ,the disc is throw...

History of Lenz's Law:- Faraday could only tell ,when and how much induced emf is produced. It was the Russian scientist H. F. E lenz who gave us in 1833 the direction of the induced emf. His experiments are known as lenz law.  Explanation :- Connect a galvanometer to coil. Take a magnet NS and move into the coil with it's north pole downlwords. The deflection in the galvanometer is towards left which indicates that the current in the coil flows in anticlockwise direction as seen from above. Hence upper force of the coil has acquired north polarity due to flow of induced current through it.  If we move the magnet out of the coil ,the deflection us towards right, indicates that the current is upper face of the coil flows in clockwise direction as seen from above, hence upper face of the coil has aquired north polarity due to flow if induced current through it.  Similarly, if the magnet is moved into or out of the coil with its aouth pole downward ...

The results of Faraday's Experiments on electromagnetic interaction are known as faraday's law  of electromagnetic induction.  1.Faraday's First law of electromagnetic induction :- Whenever magnetic flux linked with a circuit changes, induced EMF is produced. The induced emf losts as long as change in magnetic flux continue.  2. Faraday's second Law of electomagnetic Induction :- The magnitude of the emf is directly proportional to the rate of change of the magnetic flux linked with circuit.                MATHEMATICALLY                 ε  ∝ dΦ/dt                                 ε= - kdΦ/dt  Here - k is constant of proportionality .In SI k=1 ,-ve sign indicates that the induced emf gas got opposing nature ie direction of flow of current due to induced emf is such that i...