Current is the rate of flow of charge, i.e. the rate at which charges move past a fixed point in a circuit. We use the symbol I to show current and it is measured in amperes (A). One ampere is one coulomb of charge moving in one second. The relationship between current, charge and time is given by:
When current flows in a circuit we show this on a diagram by adding arrows. The arrows show the direction of flow in the circuit. By convention we say that charge flows from the positive end (
or terminal) of a battery, through the circuit, and back to the negative end (
or terminal) of the battery. This is shown in the diagram below. We measure the current with an instrument called an
ammeter.
The arrows in this picture show you the direction that charge will flow in the circuit. Note that the arrows point from the positive end of the battery, through the circuit, towards the negative end of the battery.
Interesting fact
Benjamin Franklin made a guess about the
direction of charge flow when rubbing smooth wax with rough wool.He thought that the charges flowed from the wax to the wool (i.e.
from positive to negative) which was opposite to the realdirection. Due to this, electrons are said to have a
negative charge and so objects which Ben Franklin called "negative" (meaning a shortage of charge) really have an excess
of electrons. By the time the true direction of electron flow wasdiscovered, the convention of ´positive¡ and ´negative¡ had
already been so well accepted in the scientific world that noeffort was made to change it.
A battery
does not produce the same amount of
current no matter what is connected to it. While the voltageproduced by a battery is constant, the amount of current supplied
depends on what is in the circuit.
Exercises: current
Using the relationship between current, charge, and time, calculate the current in a circuit which has
of charge passing a point every second.
Given:
Asked for: I
How much charge flows per second in a circuit with a current of
?
Asked for: Charge, Q
Given: Current
If
of charge flow past a point in a circuit in 1 second, what is the current in the circuit?
Asked for: current, I
Given: charge
I measure the current in a circuit to be
. How much charge is flowing per second in the circuit?
the study of living organisms and their interactions with one another and their environment.
Wine
discuss the biological phenomenon and provide pieces of evidence to show that it was responsible for the formation of eukaryotic organelles in an essay form
advantage of electronic microscope is easily and clearly while disadvantage is dangerous because its electronic. advantage of light microscope is savely and naturally by sun while disadvantage is not easily,means its not sharp and not clear
Abdullahi
cell theory state that every organisms composed of one or more cell,cell is the basic unit of life
Abdullahi
is like gone fail us
DENG
cells is the basic structure and functions of all living things
A scanning electron microscope (SEM) is ideal for situations requiring high-resolution imaging of surfaces. It is commonly used in materials science, biology, and geology to examine the topography and composition of samples at a nanoscale level. SEM is particularly useful for studying fine details,
