Fundamentals of Physics

Question Of The Day(AIEEE)

2012-01-16T20:23:00.000-08:00

A particle moves along the xaxis as x = u(t-1)2 + a(t-3)3

[a] initial velocity of the particle is u

[b] the acceleration of the particle is a

[c] the acceleration of the particle is 2a

[d] the particle is at the origin at time t=3 seconds

Question Of The Day(CET)

2012-01-16T20:21:00.000-08:00

A straight wire of diameter 0.5mm carrying a current of 1A is replaced by another wire of radius 1mm diameter and carrying the same current. The strength of the magnetic field far away is

[a] twice the earlier value

[b] one half of the earlier value

[c] one quarter of the earlier value

[d] same as the earlier value

Electric Current Basics

2012-01-14T22:52:00.000-08:00

Electric Current Basics

Electrostatics Basics

2012-01-14T22:45:00.000-08:00

ElectroStatics Basics

Question Of The Day(AIEEE)

2012-01-14T21:14:00.000-08:00

Find the angle of minimum deviation for an equilateral prism made of a material of refractive index 1.732. What is the angle of incidence for this deviation ?

a)60
b)0
c)30
d)90

Question Of The Day(CET)

2012-01-14T21:11:00.000-08:00

If the resistivity of potentiometer wire be ρ and area of cross section be A, then what will be the potential gradient along the wire?

[a] Iρ/A [b]I/ρA

[c] IA/ρ [d] Iaρ

Magnetic Effect Of Electric Current Notes

2012-01-13T20:09:00.000-08:00

Magnetic Effect Of Electric Current

Question Of The Day

2012-01-12T23:54:00.001-08:00

IN NPN transistor, the collector current is 24mA. If 80% of the electrons reach collector, the base current in mA is

[a] 36 [b] 26

[c] 16 [d]6

Question Of The Day

2012-01-12T23:53:00.001-08:00

Within depletion region of the pn junction diode

[a] p side is positive and n side is negative

[b] p side is negative and n side is +ive

[c] both sides are either positive or negative

[d] both sides are neutral

Question Of The Day

2012-01-12T23:51:00.000-08:00

Two batteries of different emfs are connected in series with each other and with external load resistance. The current is 3A. when the polarity of one of the batteries is reversed the current is 1A. the ratio of emf’s of the two batteries is

[a] 2.5 [b] 2

[c] 1.5 [d] 1

Question Of The Day

2012-01-12T22:54:00.001-08:00

The magnitude of earth’s magnetic field at the North pole is B₀. a horizontal conductor of length l moves with velocity v. the direction of v is perpendicular to the conductor. The induced emf is

[a] zero, if v is vertical [b] B₀lv, if v is vertical

[c] zero, if v is horizontal [d]B₀lv is v is horizontal

Question Of The Day,

2012-01-12T22:53:00.000-08:00

A vertical conducting ring of radius R falls vertically in a horizontal magnetic field of magnitude B. the direction of B is perpendicular to the plane of the ring. When the speed of the ring is v,

[a] no current flows in the ring

[b] A and D are at the same potential.

[c] C and E are at the same potential

[d] the potential difference between A and D is 2Brv, with D at higher potential.

Theory Of Relativity(Animation)

2012-01-12T00:26:00.000-08:00

A spaceship is flying a distance of 5 light hours, for example from Earth to the dwarf planet Pluto. The speed can be regulated with the upper buttons. The applet demonstrates that the clock in the spaceship goes more slowly than the two clocks of the system in which Earth and Pluto are motionless.

For Animation CLICK HERE

Diffraction of Light by a Single Slit(Animation)

2012-01-12T00:23:00.000-08:00

For Animation CLICK HERE

Interference of Light at a Double Slit(Animation)

2012-01-12T00:22:00.000-08:00

In this Animation you can vary the wavelength,spacing between the slits,angle and you can observe the effect of this on width of fringe and intensity of fringe,

For Animation CLICK HERE

Image Formation by Converging Lenses(Animation)

2012-01-12T00:18:00.001-08:00

For Animation CLICK HERE

Reflection and Refraction of Light Waves(Animation)

2012-01-12T00:17:00.000-08:00

This applet is a sort of tutorial which explains the reflection and the refraction of waves by the principle of Huygens. Explanations of each of the steps are provided in the text box. Whenever a step is finished, press the "Next step" button! You can stop and continue the simulation by using the "Pause / Resume" button. The three text fields make it possible to vary the index of refraction of both media and the angle of incidence. The medium with the smaller index of refraction (the bigger phase velocity) is painted yellow, the other blue.

For Animation CLICK HERE

Refraction of Light(Animation)

2012-01-12T00:16:00.000-08:00

A ray of light coming from the top left strikes the boundary surface of two media. (It is possible to choose the substances in both lists.) The medium which has the bigger index of refraction is painted blue, the other yellow. You can vary the incident ray with pressed mouse button. The applet will show the reflected and the refracted ray and calculate the corresponding angles:

Angle of incidence	(black)
Angle of reflection	(blue)
Angle of refraction	(red)

For Animation CLCK HERE

of a Straight Current-Carrying Wire(Animation)

2012-01-12T00:14:00.000-08:00

An electric current produces a magnetic field. This applet simulates an experiment concerning the magnetic field of a straight current-carrying wire. A large current passes through a vertical wire. You can reverse the direction of this current by using the red button. The signs at the ends of the wire symbolize the poles of the connected battery. The conventional direction of current is given by the red arrow. Note that the motion of the electrons (green dots) is opposite to the conventional direction!
A compass needle which can be moved (by dragging the mouse with pressed mouse button) shows the direction of the magnetic field (blue) at a given position. North and south pole of the compass needle are painted with red respectively green colour. The influence of the earth's magnetic field is neglected in this simulation.

For Animation CLICK HERE

Lorentz Force(Animation)

2012-01-12T00:12:00.000-08:00

This Java applet demonstrates the Lorentz force, exerted on a current-carrying conductor swing in the magnetic field of a horseshoe magnet.
You can switch on (off) the current by using the upper button ("On / Off"). The other two buttons ("Reverse current" and "Turn magnet") make it possible to change the direction of the current respectively of the magnetic field. If the corresponding checkboxes are selected, the applet will indicate the conventional direction of current (red arrows), the magnetic field lines (blue) and the Lorentz force (black arrow).

For Animation CLICK HERE

Direct Current Electrical Motor(Animation)

2012-01-12T00:10:00.001-08:00

This Java applet shows a direct current electrical motor which is reduced to the most important parts for clarity. Instead of an armature with many windings and iron nucleus there is only a single rectangular conductor loop; the axis the loop rotates on is omitted.
The red arrows indicate the conventional direction of current (from plus to minus). You can recognize the magnetic field lines (directed from the red painted north pole to the green painted south pole) by the blue color. The black arrows represent the Lorentz force which is exerted on a current-carrying conductor in the magnetic field.
The mentioned Lorentz force is orthogonal to the direction of current and to the magnetic field lines. The orientation of this force results from the well-known three finger rule (for the right hand!)

For Animation CLICK HERE

Generator(Animation)

2012-01-12T00:09:00.000-08:00

This Java applet simulates a generator which is reduced to the most important parts for clarity. Instead of an armature with many windings and iron nucleus there is only a single rectangular conductor loop; the axis the loop rotates on is omitted.
The radio buttons in the top right corner allow you to choose an AC generator (without commutator), or a DC generator (with commutator). You can change the direction of rotation by using the corresponding button. The sliding control makes it possible to vary the rotational speed. You can stop and continue the simulation with the button "Pause / Resume". This, however, does not mean a real stop of the movement, for in this case the induced voltage would be reduced to zero.
Two black arrows mark the momentary direction of movement. You can recognize the magnetic field lines (directed from the red painted north pole to the green painted south pole) by the blue color. The red arrows represent the direction of the induced current (conventional direction of current).

For Animation CLICK HERE

Simple AC Circuits(Animation)

2012-01-12T00:07:00.001-08:00

Java applet shows a simple circuit consisting of an alternating voltage source and, depending on the selected radio button, a resistor (without inductivity), a capacitor or an ideal coil (without resistance). In addition there are meters for the voltage U (blue) and the amperage I (red).
Below the drawing of the circuit you see on the left a phasor diagram; it is possible to read the momentary oscillation phases from the position of the two phasors (voltage blue, amperage red). The projection of a phasor onto the vertical axis corresponds to the momentary value of U respectively I. On the bottom right the dependence of voltage and amperage on the time is illustrated in a diagram.
The "Reset" button brings the circuit to its initial state. You can start or stop and continue the simulation with the other button. If you choose the option "Slow motion", the movement will be five times slower.
It is possible to vary the preselected values of frequency, maximal voltage and resistance respectively capacity or inductivity. The program will indicate the new value of the maximal amperage

For Animation CLICK HERE

Potentiometer(Animation)

2012-01-12T00:06:00.000-08:00

In this animation you can change position of the sliding contact.You can observe the changes in output voltages and current.

For Animation CLICK HERE

Electromagnetic Oscillating Circuit(Animation)

2012-01-12T00:03:00.000-08:00

This simulation deals with an electromagnetic oscillating circuit, consisting of a capacitor (center) and an inductor (i.e. a coil, on the right). As soon as you have pressed the "Reset" button, the plates of the capacitor will be charged, namely the upper plate positively and the lower plate negatively. After clicking on the "Start" button with the mouse, the switch will be brought to its other position so that the oscillation will begin. The same button makes it possible to interrupt respectively resume the simulation. The animation will be 10 or 100 times slower than the real oscillation, depending on the selected radio button. You can vary the values of the capacity (from 100 μF to 1000 μF), the coil's inductivity (from 1 H to 10 H) and resistance (from 0 Ω to 1000 Ω) and the voltage of the battery by using the four text fields.
The electric field of the capacitor (red) and the magnetic field of the inductor (blue) are indicated by field lines in the circuit diagram. The density of these field lines shows the strength of the corresponding field. In addition, you can see the charge signs of the two capacitor plates and arrows for the (conventional) current direction.
At the left bottom a digital clock indicates the time since the begin of the oscillation; under there you can read the oscillation period. At the right bottom one of two diagrams is to be seen, depending on the selected radio button in the lower part of the control panel:
1. A diagram which shows as voltage U (blue) and amperage I (red) vary in time.
2. A bar graph which describes the transformations of energy.

For Animation CLICK HERE