Electric current results from the movement of charges through a conductor; it can also result from chemical solutions, known as electrolysis. The electric current is a scalar quantity regardless it has direction and magnitude; besides, it’s a fundamental quantity, but why is electric current a fundamental quantity?
Why Is Electric Current a Fundamental Quantity?
Because you can easily measure the electric current, the current is a movement of charges; free electrons are the reason for the electric current in good conductors. So the electric current is chosen to be the fundamental quantity instead of the charge.
The electric charges are very small, and neither can be isolated nor measured, so they are not a fundamental quantity. In addition, instruments such as ammeters can measure the electric current; meanwhile, the charge can be measured using the ammeter.
Is the Electrical Quantity a Fundamental Quantity?
According to physics, the quantities that can be measured in physical or base fundamental units are only seven, and they are:
- Electric Current
- Amount of Substance
- Luminous Intensity
What Are Fundamental Quantities?
The quantities that can be only expressed in physical quantities should be independent quantities; if these two conditions are true, they are fundamental quantities. There are many examples of fundamental quantities such as length, time, electric current, etc.
Are Ampere and Electric Current Both Fundamental?
Yes, ampere and electric current are fundamental; however, they are not the same “fundamental.” an ampere is a unit, not a quantity, but the ampere is different from the coulomb. Furthermore, the coulomb can’t be measured due to its very small size; the coulomb is used to measure the charges of particles.
Ampere is used to measure the intensity of the electric current; an ampere is a fundamental unit; meanwhile, the electric current is a fundamental quantity.
What Does Electric Current Mean?
In electric circuits, there are two requirements, the electric current and the power; power is used in electric circuits to apply a work of force to charges to move. When charges start to move, an electric current is found; there is a movement inside the wires.
Electric current is a physical quantity that can be defined numerically and measured using instruments such as ammeters. The current is the number of charges that pass through a unit area of the wire in a certain time, so it’s the rate of charges movement. Rate quantities have many other examples like velocity.
The velocity is the rate at which the position of an object is changed; another example of rate quantities is acceleration. The acceleration is the rate at which the velocity of an object is changed; all rate quantities can be mathematically calculated. So to calculate the electric current, we use the equation I = Q/T.
How To Calculate Electric Current?
To calculate electric current, we use the equation I = Q/T; for example, if you have an electric wire of 2 mm in length with a cross-sectional area, the wire passes a charge of 20 coulombs in 40 seconds. Then, substituting in the previous equation I = 20/40 = 0.5 amperes.
Another example is if you have an electric wire 1 mm in length with a cross-sectional area, the wire passes a charge of 2 coulombs in 0.5 seconds. Then, substituting in the previous equation, I = 2/0.5 = 4 amperes.
What Are the Effects of Electric Current?
An electric current is a form of energy, and it can have several effects when passing through conductors, such as heat, magnetic, and chemical effects. Each effect has its advantages and disadvantages, for example:
Heat Effect of Electric Current
An electric current is a number of charges passing through a conductor; each conductor has a resistance; they face resistance when the charges pass through. At charges being resisted, heat is generated; the work energy is converted to heat energy because the charges do work to overcome this resistance.
This concept is used in many appliances such as toasters, iron box, water heater, etc. The main idea is to make the electric current pass through a resistance that puts work on the charges. Therefore, the work is converted to a heat that we use in our favor.
Chemical Effect of Electric Current
In chemistry, when a current passes through a solution and conducts electricity, it’s called electrolysis. Electrolysis is unique because, unlike other cases, the electrons are the only particles responsible for carrying charge. The positive ions can also carry a charge and participate in electricity generation.
For example, in copper sulfate solution, the positive copper ions and negative electrons carry charges and generate electric current. The positive terminal in a chemical battery is called the anode; meanwhile, the negative terminal is called the cathode.
Magnetic Effect of Electric Current
When a current passes through a wire, it generates a magnetic field perpendicular to the current’s direction, which is called the current’s magnetic field. The magnetic field moves in circles; their center is the wire; you can determine whether the circles are clockwise or counter-clockwise by the right-hand rule.
First, place your hand on the wire, and your thumb should be pointing towards the direction of the current. If you rotate your finger around the wire in a clockwise direction, the magnetic field rotates clockwise. If your fingers rotate counter-clockwise, then the magnetic field rotates counter-clockwise.
To sum up, the electric current is a fundamental quantity because you can easily measure the electric current; the current is a movement of charges, and free electrons are the reason for the electric current in good conductors. So the electric current is chosen to be the fundamental quantity instead of the charge.
Meanwhile, electric charges are very small, and neither can be isolated nor measured, so they are not a fundamental quantity. You can measure electric current using instruments such as ammeters. Physical quantities have many examples, such as:
- Electric Current
- Amount of Substance
- Luminous Intensity
In addition, you can calculate the electric current using a simple equation I= Q/T, where the Q refers to the charges and the T refers to the time the charges have taken to pass a point in the electric wire. Electric current has many effects such as heat effect, magnetic effect, and chemical effect.
Each effect has its advantages and disadvantages, heat effect can be used to generate heat, and it is used in many applications; for example,
- Iron Box
- Water heater
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