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# Monthly Archives: January 2014

## Maths and Science Sample Question Papers for Class X SA2

Download and practice the sample question Papers in Matsh and Science prepared by Kendriya Vidyalaya teachers for class X SAII

CBSE Maths for class 10 SA2 – 1  (more…)

## Magnetic field due to current

A spinning electron creates a magnetic field.But what about an electron inside a current carrying wire electron is spinning around its axis and revolving in loop,both simultaneously.So,what if both the situations contradict (both magnetic fields are in opposite direction ).net M.F. should be zero then. I mean what is the fate of electron in a current carrying wire with respect to its spin?

## Eddy Currents in Transformers

Why Eddy current used in transformers?

## Electric potential due to a dipole

If a point lies at a distance x from the midpoint of the dipole the electric potential is?

If the distance x is along the equatorial plane (a plane passing through the midpoint and perpendicular to the axis), the potential will be zero.

Please clarify what did you mean.

## What do you mean by degrees of freedom?

What do you mean by degrees of freedom?

Hope that your question is from kinetic theory of gases.

“The number of independent ways by which a dynamic system can move without violating any constraint imposed on it, is called degree of freedom. In other words, the degree of freedom can be defined as the minimum number of independent coordinates that can specify the position of the system completely.”

## Six degrees of freedom

Translation:

Moving up and down (heaving);

Moving left and right (swaying);

Moving forward and backward (surging);

Rotation

Tilts forward and backward (pitching);

Swivels left and right (yawing);

Pivots side to side (rolling).

## Explain a method to create Uniform Electric Field.

The simplest method of creating a uniform electric field in a region is to keep two  equally charged thin plain metal sheets of opposite charge parallel to each other. As you can see from the derivation for electric field due to a plain sheet of charge, the electric field due to a plain sheet of charge is independent of distance (provided the distance is not large compared to the dimensions of the plain sheet of charge).

So, if you keep two plain metal sheets of same charge densities but opposite kind of charge, we get a fairly good uniform electric field in between the plates.

At regions close to a uniformly charged thin sheet also we get a uniform electric field, but as distance increases it may tend to become non uniform.

## Electricity field intensity within a conductor is always zero.Why?

Electricity field intensity within a conductor is always zero.Why?

The main difference between a conductor and an insulator is that the conductors contain plenty of free electrons which are free to move throughout the conductor; whereas the insulators do not have free electrons at room temperature.

When a conductor is held in an electric field, the free electrons inside them instantly drift opposite to the direction of electric field until the electric field due to the drift balances the external electric field and the net electric field inside the conductor becomes zero.

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