How Do Watt and Volt Work Together in Physics?
Let’s suppose that there are two persons viz: P and Q, each of these is allocated a task of data analysis for a limited duration in which they have to fulfill the deadline. A person’s ability will be ascertained by how much time he takes. If person P meets the expectations of their hiring manager, he gets recruited into the company and if he does not, he fails.
So, here person P takes 2 hrs, while person Q takes 3 hrs, so here person P has more power than Q.
Now, this person has ability but he needs a push, so that push or the driving force is the potential difference.
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Relationship between Watt and Volt
Watt is the SI unit of power while Volt is the SI unit of potential difference. The relationship and differences between Watt and Volt can be understood by carefully examining the differences between Power and Potential Difference.
In terms of mathematical formulation,
P = V*I
Where, P = Power, V = Potential difference, and I = Current flowing between them
The relation between Watt and Volt can be thought of as direct, which means that Watt varies directly with the Volt. This implies the following:
When the electric power in terms of Watt increases, there is a corresponding increase in the electric potential in terms of Volt while keeping the electric current constant.
However, if the electric power Watts decreases, the electric potential in Volts decreases by the same amount, when the electric current is kept constant.
Difference Between Watt and Volt
How Does Wattage Work?
Watt: An electrical power is measured in Watts. Let’s take our hose analogy.
Imagine you are spraying water from the hose into a bucket. So, here power is the measure of how quickly the bucket is filling up.
From the Watt and Volt equation, we understand that it is a straightforward concept that power is the product of electric potential measured in volts and the current flowing through the conductor in Amperes. So, the more the wattage, the brighter is the light.
We might have seen that a 9 W LED bulb is brighter than a 6 W LED bulb.
Now, talking about voltage:
How Does Voltage Work?
Voltage: A force that makes electricity move is the voltage and it is measured in volts.
Let’s consider a hose analogy:
Imagine that voltage is the pressure in the garden hose, even if the nozzle of the hose is turned off, the pressure still persists inside it.
So, in relation to the electricity, even if we switch off the bulb (as the bulb is connected across the circuit), the voltage remains in the energized part of the circuit/ckt.
Volt and Watt Difference
Volt is 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 = 1 Watt/1 Ampere ....(2)
From eq (2), Watt is the rate at which the electrical work is performed when one ampere of current flows through the conductor on applying the potential difference of one volt across the ends of the conductor.
Now, let’s give a new meaning to the Watt and Volt Relation in terms of AC and DC:
Watt Volt Relation
Watt Related to Volt
The relation between Watt and Volt is direct. It means that Watt varies directly with the Volt. This implies the following things:
When the electric power in terms of Watt increases, the electric potential in terms of Voltage increases by the same amount while keeping the electric current constant.
However, when the electric power Watts decreases, the electric potential in Volts decreases by the same amount, while keeping the electric current constant.
Let us consider that there are two persons P and Q respectively, each of these is allocated a task of physical labour for a limited duration in which they have to fulfill the deadline. A person’s ability will be judged by how much time he takes. So, if the person P or Q meets the expectations of their hiring manager, he gets recruited into the company and if he does not, he fails.
Now, if person P does the work in 2 hours and Q does the work in 3 hours then we can ascertain that P has more power than Q. So the potential difference is the capacity created between two ends which has an empty space between them and Power is the actual energy that is transmitted between this space per unit of time.
This is all about watt and volt and their relationship. Understand the definitions and concepts to realize how they are related and grab hold of this topic well.
FAQs on Understanding the Relation Between Watt and Volt
1. What is the fundamental relationship between Watt and Volt?
The fundamental relationship is that a Watt (W) is a unit of power, while a Volt (V) is a unit of electric potential difference. Power in watts is the product of voltage in volts and current in amperes. Therefore, watts and volts are directly proportional when the electric current is held constant. In simple terms, a volt represents the 'push' or 'pressure' on the electricity, while a watt represents the rate at which that electricity is doing work.
2. What is the formula that connects Watts, Volts, and Amperes?
The formula that connects these three fundamental electrical units is known as the Power Formula. It is expressed as:
P = V × I
Where:
- P stands for Power, measured in Watts (W).
- V stands for Voltage (or potential difference), measured in Volts (V).
- I stands for Current, measured in Amperes (A).
This formula is a cornerstone of the 'Electricity' chapter in the CBSE curriculum for Class 10.
3. How is the relationship between Watts and Volts important for household appliances?
This relationship is crucial for understanding how home appliances function and consume electricity. While your home is supplied with a standard voltage (e.g., 220-240V in India), appliances are rated in Watts to indicate their power consumption. For a fixed voltage, an appliance with a higher wattage will draw more current (Amperes). For example, a 1500W geyser draws significantly more current and consumes more energy per second than a 15W LED bulb, even though both operate on the same voltage supply.
4. Can you directly compare a Volt and a Watt, or convert one to the other?
No, you cannot directly compare or convert a Volt to a Watt. This is a common misconception. They measure two different, though related, physical quantities. A Volt measures potential difference (the 'force' that moves electrons), while a Watt measures power (the rate at which energy is used). To find the power in watts, you must know both the voltage (in volts) and the current (in amperes), as shown in the formula P = V × I. Thinking one is 'bigger' than the other is like asking if a kilometre is bigger than a litre.
5. How do Volt, Watt, and Ampere differ from each other using a simple analogy?
A common and effective way to understand the difference is the water hose analogy:
- Voltage (Volts): This is like the water pressure in the hose. It's the potential force that exists even if no water is flowing.
- Current (Amperes): This is like the rate of water flow through the hose. A wider hose or higher pressure can increase the flow.
- Power (Watts): This is the total 'work' the water can do as it comes out, which is a product of both the pressure (Volts) and the flow rate (Amperes).
6. What is the difference between a Watt (W) and a Volt-Ampere (VA)?
In simple DC circuits, a Watt and a Volt-Ampere are effectively the same. However, in AC circuits, which power our homes, they can be different. Watt (W) measures the real power, which is the actual power used by a device to perform work (like creating light or heat). Volt-Ampere (VA) measures the apparent power, which is the total power flowing in the circuit. The difference between them is due to a factor called the 'power factor,' which is a key concept in AC circuits as per the CBSE Class 12 syllabus.
7. How does the Watt relate to other units of power like horsepower?
Both the Watt and horsepower are units used to measure power. The Watt is the standard SI unit of power. Horsepower (hp) is an older, non-SI unit still commonly used to describe the power of engines and motors. They are directly convertible, providing a way to compare the power of electrical devices and mechanical engines. The standard conversion is:
1 horsepower ≈ 746 Watts
