all about physics

Sunday, 16 December 2012

The Difference Between Ammeter and Voltmeter

Saturday, 15 December 2012

Potential Difference Between Two Points

Assalamualaikum my fellow friends..i'm sorry if this note quite simple..:)
We're going to learn about potential difference.

Potential Difference Between Two Points.

V_a+ iR = V_b

V_b - V_a= iR

Potential Difference between a Real Battery

V = ε – ir

Grounding circuit means connecting the circuit to a conducting path to Earth’s surface (actually to the electrically conducting moist dirt and below ground)

Thus the potential = 0

Power , potential and EMF

The net rate P of energy transfer from the emf to the charge carrier is
P = iV

The rate P,at which energy is dissipated as thermal energy in the battery is
P_r= i²R

The rate P_emfat which the chemical energy in the battery changes is
P_emf= iε

Publish by iza

Other Single LOOP Circuits

Resistance in Series

When a potential difference V is applied across resistances connected in series, the resistances have identical currents i. The sum of the potential differences across the resistances is equal to the applied potential difference V.

Resistances connected in series can be replaced with an equivalent resistance Req that has the same current i and the same total potential difference V as the actual resistances.

Req = R₁ + R₂ + R₃

Note that, when resistances are in series, their equivalent resistance is greater than any of the individual resistance.

Kirchhoff's Voltage Law

Kirchhoff's Voltage Law (or Kirchhoff's Loop Rule) is a result of the electrostatic field being conservative. It states that the total voltage around a closed loop must be zero. If this were not the case, then when we travel around a closed loop, the voltages would be indefinite.

In Figure 1 the total voltage around loop 1 should sum to zero, as does the total voltage in loop2. Furthermore, the loop which consists of the outer part of the circuit (the path ABCD) should also sum to zero.

xoxo,
HAN =)

Single LOOP

ok...hi guys...
we are going to discuss about single-loop. how to calculate the current ?? let's check it out !!

There are Energy Method and Potential Method.

ENERGY METHOD :

In a time interval, an amount of energy will appear in this resistor.

This energy said to be dissipated.

During the time, a charge will move through battery, so it will have work done.

work done = thermal energy that appears.

So, The energy per unit charge transferred

to the moving charges is equal to the

energy per unit charge transferred from them.

next, let's move to the second method....

POTENTIAL METHOD :

Loop rule : the algebraic sum of the changes in potential encountered in a complete traversal of any loop of a circuit must be zero.

Kirchhoff’s loop rule (Kirchhoff’s voltage law)

Start from low-potential terminal of the battery to the high-potential terminal.

Resistance rule : for a move through a resistance in the direction of the current, the change in potential is –iR; in the opposite direction it is +iR.

EMF rule : for a move through an ideal emf device in the direction of the emf arrow, the change in potential is + and in opposite direction it is – .

xoxo ,
HAN =)

Ammeter and Voltmeter

Assalamualaikum, today I will write to you about voltmeter and ammeter. Have you seen the voltmeter and ammeter? I'm pretty sure that you have seen them, it is a TOTAL LIE if you said that you HAVEN'T. During our experiment in the physics laboratory from the first semester until now, we have been using these devices to get the result and accomplish the requirement needed for the experiment. First of all, I would like to show you how does ammeter looks like.

Is the picture of the ammeter that I have shown is just as the same as in your memory? I'm pretty sure it is the same, otherwise either one of us have a wrong knowledge about ammeter. :)

Now, let us move on to the next device, which is voltmeter. How does voltmeter look like? Is it like the figure above?

NO, IT' S NOT. Even the secondary science students know that this is not voltmeter. :)

So, is it like this my comrades?

Yes, this is the REAL voltmeter. :)

I think I want to end up my post here. If the post is too long, I'm afraid that my comrades will feel boring, as you know I am just a beginner,so, forgive me for my mistakes and my weakness in posting the post. Arigatou Gozaimas shita~!

Written by : Quraisya

The Basic Relationship Between Subatomic Particles, Electricity and Circuit

As all of us know, everything occurred in this world related to science. There are three main subjects in science which is Chemistry, Physics and Biology. Hence, in analyzing the phenomenon involved in circuits, we will find that this phenomenon related to Chemistry and Physics. How is it related? Let’s take a deep breath and think about it wisely.

An atom has a nucleus. As all of us know, nucleus consists of proton (which is positive charge) and neutron (which is neutral). The small charge particle, electron exists out of the nucleus, and attached to the shell. The Chemistry and Physics related when a complete circuit (circuit that connect successfully) , there is electricity, and electricity comes from resulting energy of the charged particles existence ( such as electron and proton) either statically or accumulation.

The common phenomenon of electricity is lightning strike. Electrically charge will explode a flux. Hence, we need to find a way to safely contain and control this flow of charge particle as we need to use the electricity in a circuit. A battery can take over the role above. In circuit, the battery is important to provide the voltage and current. Battery is a device that converts from chemical energy to electrical energy. Battery has two terminal which is plus(+) and minus(-), which refers to positive and negative charge of proton and electron. Electron will move out from the negative terminal of the battery and attracted by the positive terminal of the battery. Electron move from negative terminal to positive terminal with right kind of material connected to the battery.

Here is an example of a low voltage battery (1.5V) being to create some light. Connecting a light bulb to this battery, we have created SIMPLE CIRCUIT, a PATH for ELECTRON to TRAVEL. A light bulb does two things, it introduces some of the resistance into the circuit, reducing the flow of electrons, so that the metal wire won’t get hot and it converts electrical energy to light energy.

Now, I would like to post a video related to this basic relationship. :)