Basic Electricity

Electricity

We use electricity to transfer energy from one place to another.
The energy is carried by electric current which flow through cable
(APP: from power station to homes)

In a simple circuit (Diagram: battery, bulb), the battery transfer energy to the chargee, and keeps it circulating round the circuit. The bulb transfer energy to the surroundings as heat and light.

Electric Current

Electric current is a flow of electric charges. The lamp lights because charged particles are moving through it.

Q:Why the ammeter is connected in series with other circuit element?

Current is measured by ammeter. Ammeter is placed in the circuit so that electrons pass through it.

Electric current is defined as the rate on charge flow (Q/t).
Meaning, the more electrons (Q) that pass the ammeter in one second(t), the higher the current.

[Without battery in the circuit]
- A copper wire consists of copper atoms and free electrons. All metals have a structure like this.

[With battery in the circuit/ battery is attached to the copper wire](Diagram:)
-The free electrons are attracted to the positive terminal. They all move slowly in the same direction through the wire with 'drift velocity'.

Diagram usually show the direction of 'conventional current' going from positive to negative.
Meanwhile, the electrons are flowing the opposite way.

Conductor Vs Insulator

Good conductors are having millions of free electrons in just mm3 volume.

In an insulator, almost all the electrons are firmly fixed to their atoms.

Semiconductors are neither good conductors nor good insulators.

~ Mind my Language throughout the Writing, May it Benefits You ➽💕

Comments

Electric Potential

Electric Potential, V If Ali wants to move his charge towards the charged sphere on the left, he has to push against the repulsive force between the two spheres (because both are positively charged) Ali is actually doing work (when he push) , Remember W= f.s ! At the same time, Ali's charge gains electric potential energy . If Ali let go his charge, it will move away from the sphere, it looses electric potential energy. The electric potential at a point is telling us the potential energy of each coulomb of charge . When you move a charge in an electric field its potential energy changes. This is analogous to moving a mass in a gravitational field. Electric potential is a scalar quantity. Thank you, Mdm Ummi Atiah KMPk ~ May it Benefits You ➽💕

Root Mean Square Current (I rms)

Root Mean Square Current As mentioned in the previous post , the value of AC is always changing. Then, how do we measure its value??? We could not use the maximum value of the current Io, because it only occurs at a moment. The average current is ZERO . Hence, one effective value that we could use the root mean square value. Irms . The formula for Irms is given by: where Io is maximum current. Irms is the value that is equivalent to a steady direct current . We can investigate this by comparing 2 circuits containing lamp each. circuit 1 uses battery as the source, while circuit 2 uses a.c. supply. AC supply is adjusted so that both lamps are equally bright. At this point, DC and AC supplies are transferring energy to the lamps at the same rate (Power). By equating the Power of both circuits, we can deduce the equation of Irms as above. Therefore, the d.c. voltage equals the r.m.s. value of the a.c. voltage. From the the graph below and th...

Magnetic Field

Magnetic Field, B To define Magnetic field, we start with the word field. Field means a region or space. The magnetic field is defined as a region where the magnetic force can be felt. In other words, a force (repel/attract) can be felt in the region. Bar Magnet We will find that 2 North(N) poles will repel if we bring the poles of two bar magnets together. Same goes to that of 2 South(S) poles. However North and South pole attracts. The strength and direction of the field are represented by lines. Knowing that, the direction of magnetic field is from North to South. Magnetic field is able to be detected by 1) Compass (have been used over 2000 years 2) Hall Probe Applications: Swipe cards, Video tapes & Computer discs -use magnetism to store information. History: In 1819, Hans Christian Oersted noticed that a compass needle was deflected by an electric current in a nearby wire. Remember!! the compass is used to detect any existance of magnetic field. By th...

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