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There are two TYPES of magnets PERMANENT and temporary... The PERMANENET magnets have a charge in them... The temporary magenta are made by passing current through a soft IRON piece

The flux linked with a coil due to the MAGNETIC field of ANOTHER coil is called MUTUAL induction.

Electric FIELD is a CONSERVATIVE field. Field lines of conservative fields must ORIGINATE and TERMINATE at different points.

The PROPERTY of attracting small PIECES of IRON was REFERRED to as MAGNETISM

Dipole moment is commonly known as ELECTRIC dipole moment ...We define the electric dipole moment p (also called the electric dipole), which has charges +Q and -q, and with r, the vector from the negative to the positive charge .......Note that since r is a vector with a certain direction, so is p. Simplistically here it points from negative charge to positive charge.......The SI units are Coulomb-meter . This article is limited to static phenomena, and does not describe time-dependent or DYNAMIC POLARIZATION. The magnitude of dipole moment DETERMINES the electric field strength..... Thank you ;)

Electrical force on a point unit CHARGE which is at a distance x, exerted by a point charge q = electric field =

the direction of electric field is ALONG the line joining the charges.

variation of electric field with distance from the point charge =


The electric potential at point P (at distance x from origin) due to the electric point  charge q at the origin = V
     V = energy REQUIRED to move a unit charge q₀ from infinity, against the electric force due to charge q, to the point P at a distance x away from q.



the variation of electric potential with distance is 

The ELECTRIC DIPOLE moment P is defined to be the product of the charge and the DISPLACEMENT vector between the two charges that make the dipole.  it is a vector quantity.

   its direction is from the NEGATIVE charge to the positive charge along the AXIS of the dipole.

Dry ice is often used in the food industry, where it can preserve perishable items and CARBONATE LIQUIDS. Dry ice can also be used to preserve medical specimens, freeze off warts, and even to get rid of some bugs. Dry ice also prevents the growth of BACTERIA. Campers have another use for it: they can KEEP food fresh for a longer PERIOD of time.

In physics , A dipole is a pair of equal and opposite charges seperated by a small diatance..Dipole moment is the product of magnitude of charge and the distance between them.....The dipole moment ( μ) is defined as the product of the magnitude of the charge, e, and the distance SEPARATING the positive...if there is an excess of positive charge on one END of the MOLECULE and an excess of negative charge on the other, the molecule has a dipole moment (i.e., a measurable TENDENCY to rotate in an electric or magnetic FIELD) and is therefore called polar.

As the PROTON is at rest, v=0
From Lorentz's equation,
F = Q(v x b) = 0 (As v=0)
THUS, no force is experienced by the proton.
So, it will not tend to move in any direction.

Radius is APPROXIMATELY    25.637/2 (DIAMETER is 25.63 UNITS)
so radius is 12.819 mm (APPROX)

A Superconductor is a material that can CONDUCT electricity or transport electrons from one atom to another with no resistance. This means no heat, SOUND or any other form of energy would be released from the material when it has reached "CRITICAL TEMPERATURE" (Tc), or the temperature at which the material becomes superconductive.
 

Let SPS' be a convex mirror surface separating a rarer medium of ABSOLUTE refractive index n₁ from a DENSER medium of refractive index n₂.Let P be the centre of curvature of the surface .PC is the radius of curvature R of the surface.Let a point-object O placed on the principal axis PC produced backwards.An INCIDENT ray of light OA,after reflection at the point A on the surface,bends towards the normal CAN and goes along AI in the denser medium.Another incident ray OP falls on the refracting surface normally and goes un-deviated into the denser medium.The 2 refracted rays meet at the principal axis at I which is the real image of O.
Suppose the angle of incidence OAM=i,the angle of refraction IAC=r ,Po=-u,PI=+v and PC=+R.According to the coordinate geometry sign convention,u is -ve while v and R is +ve.Let α,β,γ b the angle made by OA,IA,Ca respect. with proncipal axis.Let H be the height of the normal AM dropped from A on the principal axis.Now,in ΔCOA,
i=α+γ
γ=r+β........[in CIA]
or r=γ-β
by snell's law:
sini/sinr=n2/n1
or n₁ sin i= n₂ sin r
or n₁i=n₂r......................[since the spherical mirror is of small aperture]
subtitute values
n₁(α+β)=n₂(γ-β)
or,n₁+α+n₂+β=(n₂-n₁)
therefore,α=tanα =AM/Mo=Am/Po=h/-u
β=tanβ=Am/Mi=AM/PC=h/v
γ=tanγ=AM/MC=AM/PC=h/r

n₂(h/v)+n₁(h/-u)=(n₂-n₁)h/r
orn₂/v-n₁/u=(n-n₁)/R
therefore the required eq. is
n/v-i/u=(n-1)/R

They are used to  store energy or electricity to give a BACK up for an electric device ..to stop instant fluctuation.. they are  usually are found in fans and electric motor 
lets take an example of a fan ....consider a fan rotating on it AXIS ,and then somehow you switch the BUTTON off..then also fan will rotate but now with lower speed and then SUDDENLY it STOPS ...these rotation after switching off is due to capacitor..

You will be ADD blue litmus PAPER in distilled water it will remains same....When you add this litmus paper in acid solution then blue litmus paper CHANGES to redWhen U add this in base solution it turns red to blue......

Upward THRUST is equivalent to the WEIGHT of the FLUID displaced by the object IMMERSED in the fluid.

With the help of our atmosphere.... ACTUALLY they need atmosphere to TRAVEL.... And when we PRODUCE sound it propagate and travel in the form of TRANSVERSE WAVES....

Sound WAVES require an atmosphere or an air to  propagate and we know that our NATURAL satellite(moon) has no atmosphere in it...so sound waves can't travel and there will be no COMMUNICATION between speaker and listener ....hence we require RADIO waves

Electricity can be GENERATED in many ways but basic need for that is electrolyte or ion or current
electricity generated by water -
hydroelectricity
Electricity generated from water is entirely renewable,
process REQUIRES dam, tunnel and turbine generally when turbine is SWITCHED on electricity GENERATES

Newton gave three laws.
First LAW -
An object at rest continues to be at rest and an object in motion continues to be in motion till an external force acts on it.
Second law -
The force on an object is directly proportional to the acceleration of the object.
F = ma
Third law -
EVERY action has an EQUAL and opposite reaction.

Weight = The force acting on a body DUE to gravity.
Mass = The proportionality constant of the RELATION force is directly proportional to acceleration.
Gravity = The attractive force exerted by the earth on other objects.

It is a UNIT USED in MECHANICAL ENGINEERING CALCULATIONS basically.
1 HP=746W

Force = mass * ACCELERATION   by Newton's law.

acceleration a = 30 N / 5 kg = 6 m/s²

  FINAL velocity = v,      initial velocity = U,        time duration = t
     we know from equations of dynamics/kinematics:  
              v = u + a t
         t = (v - u) / a = 12 / 6 = 2  seconds.

1) CONVEX mirror diverges and reflects the rays falling on it, and hence it always GIVES a virtual image.
    Concave lens transmits the light rays to the other side and diverges them. So only a virtual image is formed.

2)
      Speed of light in a medium = speed of light in vacuum / REFRACTIVE index 
 Since refractive index is less in Kerosene, the speed of light is more in kerosene.

3.
  The BOILING point decreases at HIGHER altitudes, as the atmospheric pressure of air is less. 

The VOLUME of the wire REMAINS same when it is recast.
       A₂ = 2 *A₁       and           L₂ = L₁ / 2          
 
 RESISTANCE R = ρ * L / A
      R₂ = ρ L₂ / A₂ = ρ L₁ / (2 2 A₁)  = R₁ / 4   = 100 Ω / 4 = 25 Ω

  HENCE resistance becomes 1/4 th.
 
You can also SAY that, resistance is proportional to the length and inversely proportional to the area of cross section.  Hence, the resistance becomes 1/2 * 1/2 times initial.

Not is a UNIT of speed equal to ONE nautical mile 1.852
!km/hr=0.539957

Room floor AREA : 7 m * 10 m
mass of air :  250 kg 
Temperature T₀ = 34⁰ C
T₁ = 24° C

Air density 1.25 kg / m³   - let us TAKE that this is the density at 34⁰ C
Volume of the room  = mass of air / density = 250 / 1.25 = 200 m³
Height of the room = volume / floor area = 200 / 70 = 2.855 m
==================
shc of air : specific heat CAPACITY of air = 1010 J/ kg/ °K 
Heat extracted when air is cooled from 34° to 24°C : ΔQ = m s ΔT
           = 250 * 1010 * (34 - 24) = 2,525 KJ
======
The actual energy needed (to be extracted) to cool the room is more than the calculated value.  One needs to cool the walls also, while cooling the air in the room.  The walls try to heat the room continuously.  The air outside the room also tries to heat the room.  So that additional heat is also to be extracted out.

Tap water may have a density of  1000 kg/m³
very dense and STRONG salty water may have a density of  1050 or 1060 kg/m³

Let a solid have a MASS of  M kg and a volume of V m³, and a density of  d kg/m³.
Let the gravity be G = 10 m/sec².

     Loss in weight of the solid in tap water = V * 1000  kg 
     Loss in weight of the solid in salty water = V * 1050 kg

The loss in weight in salty water is  50 kg per m³ volume of the solid,  more than the loss in weight in tap water.

.C)3.6*10^6 is the ANSWER

The LIGHT waves and sound waves travel a few km.  Their speeds are 300,000 km/s and 340 m/sec.  So there is a difference of seconds of time between seeing a flash and hearing a thunder.
The speed of sound increases with the DENSITY of the medium.  The particles vibrate in the medium to transfer sound ENERGY.  If the particles are closer to each other, then the vibration of one particle induces more easily the vibration in the next particle. Then sound energy is transferred quicker. 
When a moving particle collides with a stationary particle, part or full of the kinetic energy of the moving particle is transferred to the stationary particle.

Archimedes immersed the crown in water.  He noted the difference in water levels to find the volume of water displaced.  He measured the weight by a balance.  Then found the density of the crown.  The pure gold crown is denser and weighs more than impure crown as impurities such as silver, copper are lighter than gold.
He calculated the density of pure gold and density of gold in the crown.

Mechanical work = Force acting on an OBJECT * displacement of the object.
                          = torque acting on an object * angle through which object rotates
               = the change in the kinetic energy of the object. (initial - final)
         The SI unit is Joules.

Positive work means the system or the body in context  has done work.  Negative work means some external system or environment has done work on the system or body.
 
 If a body falls from a height then gravity does work on the body.  So the work done by the body is negative.  So its energy increases.
If a moving ball on a floor comes to rest, then the work done by the ball is positive.  So its energy decreases and final kinetic energy is less than the initial.

If an OBJECT is placed between two plane MIRRORS inclined at an ANGLE Ф,then the NUMBER of images FORMED is

n=