Last Updated on November 12, 2021 by Jahangir

In this article, we will discuss the formula of power in electricity. The formula tells us that the voltage is proportional to the energy that passes through a wire. In other words, it shows how much energy a wire can carry without burning out.

As an example, a thin copper wire can carry a large amount of electrical current for a very long time before it burns out due to overheating. A thin copper wire also has a very high resistance and cannot carry large amounts of current at once, but for a short time, it can carry as much electrical power as a thicker iron wire.

Another way to explain this idea is that thin wires have very low resistance and so they can quickly deliver large amounts of electricity (or energy), and bulky wires (those with larger diameters, such as welding rods) cannot easily do the same task at once.

**Power and Energy**

Energy is the natural resource that humans need to run and maintain their machinery. They can be used for light, heat, or motion. Power is an energy source that produces a certain amount of work per unit of time and power is measured in watts (W). The more powerful we are, the faster we can do work.

Power and energy are related because they both produce something useful for machines. Power generates electricity which powers machines. Likewise, energy provides the work that machines need to do.

**What is power in electricity?**

Power in electricity is the ability of an electric charge to do work. Current electricity is generated by generators that use a magnet rotating within a coil of wire to create a magnetic field. In this process, electrical energy is produced from mechanical energy as it moves from one place to another.

The SI unit for the measurement of energy is the joule (J). A watt-second (W·s), or joules per second represents one-watt times 60 seconds. Thus, the amount of power that is generated depends on several factors. Electric charge (Q), volt (V), and current (I) are all proportional to one another; therefore, if we increase either any one of these for example by increasing V or I, amp then it automatically increases Q as well in the circuit.

**Learn the Formula Of Power In Electricity**

The power formula is a mathematical equation that calculates the power of a number and compares it to one. The equation is:

P=VXI.

There are three variables in this equation: “P”, “I” and “V”. P represents power, V represents voltage and I represents current. Voltage tells us how much potential difference has, while current tells us how much electron flows in a close electric circuit. By inserting values, you can calculate power.

The above formula is the basis of all-electric circuits and systems.

The equation for calculating power in an AC circuit is given by the formula P = V x I. This formula is also acceptable for DC circuits. By inserting into that equation, you can calculate power. This formula is used to determine the quantity of electricity consumed by any circuit or system, but it does not take into consideration losses. The losses depend on the electrical resistance that prevents the flow of the electric current. The greater the voltage and current, the greater amount of power that flows through a circuit.

**Electrical Power Rating**

The power rating of every electrical appliance tells you how much electricity it requires so that it will function properly. Watts (W) or Kilowatts (kW) are usually used to describe these measurements. This measurement tells you how much power is consumed by an appliance. The size of the circuit should be considered before determining whether this rating will suffice, but if not then the rated wattage may have to over-shoot in order to get what you need or desire from that electrical device.

**How to calculate power if you have only the voltage and resistance of a device?**

In this case, you need to apply ohm law and then you need to determine the ampere/current of the device to calculate the power.

The ohm’s law equation states that the current I is equal to the voltage V divided by resistance R. This law plays a significant role in science, electronics and electromagnetism.

V=IR

Ohm’s law can be used to determine the power (watts) of electric current passing through resistors or capacitors with two terminals connected between an emf source and its load side.

The voltage of the device is the electric potential difference between two points in an electrical circuit. If you know that, then all you need to do is find out the resistance of the device to calculate power.

**How to Use Ohm’s Law to Determine Current**

In order to calculate current, it is necessary to know the voltage and resistance. This can be done by using Ohm’s law:

V = IR

To calculate the current in a circuit, you take the voltage (measured in volts) and divide it by the resistance (measured in ohms). The result is expressed in amperes.

**Calculating power using current and voltage**

If we know the voltage and current of a device, we can easily calculate the power of the device using the Formula of Power in Electricity i.e. P=VI.

**Calculating power using resistance**

As an example, if you have a light bulb that has a resistance of 110ohms and the voltage across the light bulb is 220volts, then what would the current be?

In this case, at first, we need to apply ohm’s law to determine the current of the light bulb.

Here, V=I*R

220=I*110

I=220/110

I=2Ampere

Since we get the ampere, now we can determine the power consumption of this device.

We know the Formula Of Power In Electricity is P=VI

Here,

P=220*2

P=440 watt

**Energy Usage**

Energy usage is the amount of energy used over a certain period of time. It can be measured in kilowatt-hours (kWh), which is how much electricity it would take to power an electrical appliance for one hour. The average American household uses around 5,00 kWh of electricity per year, but this varies depending on how big your house is and what you use your appliances for.

An easy way to check if your electric bill is too high, you can check our articles-

**FAQs**

*Having seven years of experience in the Engineering field, Md Jahangir Alam is qualified in the electrical and electronics engineering field. He is the Chief of our organization and he has provided guidance to a hundred and fifty Engineers in their migration skills assessment process for Engineers Australia. He has played a significant role in the organization CDRFOREA since it was established back in 2013.*