Dimensions of Electrical Resistance

Electricity can be dangerous if you are unaware of what you’re doing, but it can be a handy and powerful tool to have in your toolbox if you understand the concepts behind it. Understanding how electrical resistance works is the first step in understanding how circuits work. Once you know circuits, you’ll understand how almost all of our modern electronics work – from your phone to your computer to your microwave to your car (and everything else in between). Understanding electrical resistance starts with answering the primary question – What is electrical resistance?

What is Electrical Resistance? 

Resistance in an electric circuit measures the energy required to push along the steady flow of electrons through a component. The higher the resistance, in other words, the harder it is for electricity to flow through that part of a circuit—so you can’t send as much power through it. You’re used to thinking about resistors in terms of watts because that’s how power gets calculated when running across circuits. But ohms are just as common—or more so—in talking about voltage and current flows.

Electrical resistance is also known as ohmic resistance. The symbol of ohmic resistance is the Greek alphabet omega (Ω). The voltage causes the current to flow. Free electrons that are trapped in the conductor collide with the conductor’s atoms while they are being drawn through. Due to obstructions or collisions, the flow rate of electrons or current is restricted. As a result, there is some resistance to the flow of electrons or the current. In other words, the tendency of a substance to resist the flow of electricity is called resistance.

The electrical resistance of a conducting material will:   

• Depend on the length of the material

• Inversely proportional to the area across which the force is applied

• Depend on the current temperature

• Depend on the characteristics of the material

What is the Formula of Electrical Resistance?

The symbol for electrical resistance is R, and you’ll use it in units of ohms. In simple terms, it’s a way to measure how much opposition a given material puts up when current flows through it. Think of it like a rubber band — stretchy materials will have low resistance (they’re easy to push through), while non-stretchy materials will have high resistance (it takes more force to push them through). Resistance can be either physical or inherent to specific objects.

Mathematically we can represent electrical resistance in three different formulas:

Formula One: As per Ohm’s Law

R = V/I

Here, 

V represents voltage

R represents electrical resistance 

I represents the electric current

Formula Two ( Power & Voltage)

The power delivered is a function of voltage and current.

P = V * I

If we use I = V / R in the above-provided formula, you will get:

P = V2/R

Consequently, we get the formula for the relationship between voltage and resistance:

R = V2/P  Ω

Formula Three (Power & Current)

We already know that:

P = V * I

Now, by putting V = I * R to the above equation we get:

P = I2  * R

Now electrical resistance is the ratio of power and the square of electrical current. 

Mathematically, it can be represented as:

R = P / I2  Ω

Formula Four: In terms of resistivity

R = LA

Here, 

L represents length of conducting wire,

A represents cross section area of wire, and 

represents the resistivity of the wire.

Effects of Temperature on Different Electrical Resistance

The electrical resistance of all materials is affected by temperature change. The result will be different for different materials.

On metals, resistance increases with the increase in temperature. The increase of the resistance is large for the average range temperature. On alloys, resistance increases with temperature, but it is small and irregular. The ohmic resistance of insulators, electrolytes, and semiconductors reduces with the increase in temperature. Once the temperature is increased, several electrons will be created.

How to Calculate Electrical Resistance?

Resistors play a crucial role in electronic devices. However, it’s sometimes not obvious how to find out what value resistor you need for your circuit. The two main factors affecting how much current a resistor can handle are its colour code and tolerance (how close together multiple resistors of that colour-code value can be and still function correctly).

What is the formula for the dimension of electrical resistance?

The word resistance refers to the current opposition to the flow of electrons, which is defined by dividing voltage by current. Resistance may be denoted in mathematical form as:  

[ML2T-3I-2].

Conclusion

Knowing what electrical resistance is and how to calculate ohmic resistance by understanding each component of the electrical resistance formula is necessary for every physics student. 

Electricity is a powerful tool, and understanding the basic concepts of electricity, such as ohmic resistance and how to compute the dimensions of electrical resistance, will become a powerful tool in your toolkit.