[Physics Class Notes] on Volt – Unit of Measurement Pdf for Exam

A force that drives electricity in the circuit is the voltage and it is measured in volts. So, the measuring unit of voltage is Volts.

Let’s Consider an Analogy:

Imagine that voltage is the pressure in the watering pipe, if the nozzle of the pipe is turned off, the pressure still persists inside it. 

So, if we relate this analogy to electricity, even if we switch off the bulb (as the bulb connected across the circuit), the voltage persists or remains in the energized part of the circuit/ckt.

In this article, we will learn about the volt unit of measurement in detail.

Volt and Watt 

We define the Volt measurement as the measure of the potential difference across the ends of the conductor or a conducting terminal of the wire.

Let’s have a look at equation (1):

 P = V * I

1 Watt  = 1 Volt * 1 Ampere

Or,

[1 Volt=frac{1Watt}{1Ampere}] ….(2)

From eq (2), we understand that the Watt is the rate at which the electrical work is performed when one ampere of current flows through the conductor/medium on applying the potential difference of one volt across its ends.

Difference Between Volt And Watt

Let’s suppose that there are two sportspersons viz: A and B, each of these is allocated a task of running for a limited duration in which they have to reach the end. A person’s ability will be determined by how much time he takes. If a sportsperson A meets the reach the location in minimum time, he gets the first prize and if he does not, he is out.

So, here person A takes 3 minutes, while the sportsperson B takes 3 minutes 40 seconds, so here person A has more power or capability than B. 

Since this person has ability but needs a push or potential, so that push or the driving force (motivation) is the potential difference.  So, Volt is the measuring unit of voltage.

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In the above text on the difference between volt and watt, we understand that voltage can be compared to the driving force that helps us to do better in our lives. Now, let’s understand how wattage works. Also, volts are measured in an electric circuit.

What is Watt?

Electrical power is measured in Watts. Let’s consider an analogy to understand what Watt is.

Imagine you are sprinkling rose water into a cup. So, here power is the measure of how quickly the cup is filling up. 

From the Watt and Volt relation equation, we understand that it is a plain concept that power is the product of electric potential measured in volts and the current flowing through the conductor in Amperes. So, the more is the wattage, brighter is the light or more is the power to do any task in minimum time, the more is the wattage. 

For Example:

We might have seen that an athlete with hard practice wins the game, i.e., he has more wattage. Similarly, in Physics, a tube light of 18-W has more wattage than a 14-W tube light.

Relationship Between Watt and Volt

From the above example, we inferred that power is the ability of sportsperson A to meet the deadline in 3 minutes. In terms of Physics, the rate of doing work is power and it is measured in Watts. 

We also understood that sportsperson B also can reach the goal; however, the coach gives him a driving force or the motivation to meet his expectations by making him practice more in the field. Now, when ‘B’ gets a voltage or motivation, he gets into the flow and reaches the end in less time than before, let’s say, 2 minutes 59 seconds. 

In terms of Physics, the push or the driving force is the potential difference between the time he took earlier and the time he took now to reach the final position and it is measured in Volts.

Relationship Between Watt and Volt

In this undergoing interview process, when the coach saw the caliber in B and he motivated him to reach the goal, he could observe when ‘B’ got ‘positivity’ (voltage), he did his work with a laminar flow or fluently. So, when the motivation (voltage) gets multiplied with his potential or ability, B gets the power to work efficiently in 2 hrs 50 seconds, which was 3 minutes 40 seconds before. 

So, mathematically, we can express the above scenario in the following manner:

                   P = V * I……(1)

Equation (1) is the Volt-Watt Relationship Equation.

Here,

P = power that is measured in Watts

V = potential difference applied across the ends of the conductor through a source like a battery or a cell, which is the volt measurement.

I = the current or the flow of electrons through the conductor or a wire and it is measured in Amperes or simply ‘A’.

If we have to determine the apparent power in an electric circuit, it is the Voltage Ampere or VA. 

An electron volt is a measure of the kinetic energy gained by an electron accelerating from the resting potential through the potential difference of one volt.