Friday, July 9, 2010

Electromagnetic Induction


Electromagnetic Induction :

The finding that electric current can produce magnetic fields led to the idea that magnetic fields could produce electric currents. The production of emfs and currents by the changing magnetic field through a conducting loop is called induction.

Magnetic flux

The magnetic field through a loop can be changed either by changing the magnitude of the field or by changing the area of the loop. To be able to quantitatively describe these changes, magnetic flux is defined as Φ = BAcosθ, where θ is the angle between B and the direction perpendicular to the plane of the loop (along the axis of the loop).
I hope the above explanation was useful.

Wednesday, June 30, 2010

Explain Wave Motion


Let us understand what is Wave Motion,

The easiest wave to visualize is a water wave. When a pebble is dropped in a calm pool of water, ripples travel out from the point where the pebble enters the water. The disturbance travels out from the center of the pattern, but the water does not travel with the wave. Mechanical waves—such as water waves, waves on a rope, waves in a spring, and sound waves—have two general characteristics:

* A disturbance is in some identifiable medium.

*Energy is transmitted from place to place, but the medium does not travel between two places.

For the sake of simplicity, idealized one-dimensional waves on a rope and two-dimensional water surface waves with no friction-like forces provide the wave model. For ease of analysis, a pulse that is a single short wave will be used to illustrate wave characteristics that also hold true for more complex waves.

Hope the explanation was useful, now let us study about the types of waves.

Monday, June 14, 2010

States of matter

Let us study about states of matter,
Solids are formed when the attractive forces between individual molecules are greater than the energy causing them to move apart. Individual molecules are locked in position near each other, and cannot move past one another. The atoms or molecules of solids remain in motion. However, that motion is limited to vibrational energy; individual molecules stay fixed in place and vibrate next to each other. As the temperature of a solid is increased, the amount of vibration increases, but the solid retains its shape and volume because the molecules are locked in place relative to each other.

Liquids are formed when the energy (usually in the form of heat) of a system is increased and the rigid structure of the solid state is broken down. In liquids, molecules can move past one another and bump into other molecules; however, they remain relatively close to each other like solids. Often in liquids, intermolecular forces
pull molecules together and are quickly broken. As the temperature of a liquid is increased, the amount of movement of individual molecules increases. As a result, liquids can “flow” to take the shape of their container but they cannot be easily compressed because the molecules are already close together. Thus liquids have an undefined shape, but a defined volume.

Gases are formed when the energy in the system exceeds all of the attractive forces between molecules. Thus gas molecules have little interaction with each other beyond occasionally bumping into one another. In the gas state, molecules move quickly and are free to move in any direction, spreading out long distances. As the temperature of a gas increases, the amount of movement of individual molecules increases. Gases expand to fill their containers and have low density. Because individual molecules are widely separated and can move around easily in the gas state, gases can be compressed easily and they have an undefined shape.

Plasmas are hot, ionized gases. Plasmas are formed under conditions of extremely high energy, so high, in fact, that molecules are ripped apart and only free atoms exist. More astounding, plasmas have so much energy that the outer electrons are actually ripped off of individual atoms, thus forming a gas of highly energetic, charged ions. Because the atoms in plasma exist as charged ions, plasmas behave differently than gases, thus representing a fourth state of matter. Plasmas can be commonly seen simply by looking upward; the high energy conditions that exist in stars such as our sun force individual atoms into the plasma state.
Hope the above explanation helped you.

Wednesday, June 9, 2010

Vector Addition

Let us study about Vector addition,

Two or more vectors may be added together to produce their ADDITION. If two vectors have the same direction, their resultant has a magnitude equal to the sum of their magnitudes and will also have the same direction.



Similarly orientated vectors can be subtracted the same manner.



In general, since vectors may have any direction, we must use one of three methods for adding vectors. These are, the POLYGON METHOD, PARALLELOGRAM METHOD and the METHOD OF COMPONENTS.
Hope the above the explanation helped you.