# Ohm’s Law and Resistance

Ohm’s Law explains that the voltage difference between two points is directly proportional to the electric current passing through the resistance. The formula to calculate this relationship is V=IR. Georg Simon Ohm, a German scientist, discovered this Law. Let’s continue learning to expand our knowledge of Ohm’s Law, resistance, and its applications.

## Ohm’s Law Definition

Voltage, current, and resistance are the fundamental components of electricity. Ohm’s Law establishes a straight forward correlation between these three factors. Ohm’s Law says that when electricity flows through a conductor, the amount of electricity is related to the voltage applied. This means they are directly connected. In other words, the electric current increases proportionally if you increase the voltage.

## Ohm’s Law Formula

According to Ohm’s law, an increase in voltage (V) leads to an equivalent increase in current (I). However, the current decreases as the resistance (R) increases. Ohm’s law is represented by the formula V=IR. Calculate the current-resistance magnitude using the appropriate formulas.

I = V/R, and R = V/I.

The symbol for resistance is Ω. This is also called “ohm”.

## Ohm’s Law Magic Triangle

The Ohm’s Law Triangle, also known as the “Ohm’s Law Magic Triangle,” is widely used by electricians and engineers. This triangle provides a visual representation of Ohm’s law formula V=IR and makes it easy to remember how the three variables are related. The triangle contains three sides- voltage (V), current (I), and resistance (R)- with a symbol representing each one. In the lower right corner is the symbol of “equals,” which points to the formula.

You can easily calculate any of the three variables using Ohm’s Law magic triangle when given two others. For instance, if you know both voltage and current values, you can easily calculate the resistance using the formula R=V/I. In this way, Ohm’s law triangle helps simplify electricity-related calculations.

## How to Verify Ohm’s Law

To verify Ohm’s Law, we need to conduct a simple electrical circuit experiment. Here are the steps:

• The circuit includes a nichrome wire and is monitored by a voltmeter and ammeter.
• To measure the potential difference in a wire, use a voltmeter. To measure the electric current, use an ammeter. Both measurements can be obtained by passing a current through the wire.
• We calculate the ratio between potential difference and electric current.
• Measure the potential difference to electric current ratio again after increasing the current.
• The ratio mentioned will remain the same for both instances, proving the validity of Ohm’s Law.

## Applications of Ohm’s Law

Ohm’s Law can calculate voltage, current, or resistance in a linear electric circuit if two out of three values are known. Ohm’s Law also simplifies power calculation. The formula to calculate power is P=VI, where P represents the rate of energy delivery or consumption.

The main applications of Ohm’s Law are:

Electrical engineering: Ohm’s Law is used in electrical engineering to calculate the properties of electricity and its power.

Electronics: This Law is applied to determine the values of capacitors in electronics.

Building Wiring: This Law helps electricians the safe levels of current use when wiring buildings.

– Telecommunications: Ohm’s Law is used in telecommunications to calculate the best resistance, capacitance, and inductance values for various circuit designs.

## Resistance Definition in Electricity

The opposition that a conductor, like a copper wire, has to electrical current flow is known as resistance. Current flow decreases as resistance increases.

Resistance is an important concept for electricity and electric circuits because it defines how much voltage needs to be applied to produce a certain amount of electric current. The higher the resistance, the more voltage is needed to produce an electric current.

## Water Pipe Analogy for Ohm’s Law

To understand Ohm’s Law, you can use an analogy of water flowing through a pipe within a closed electric circuit. The flow of water represents the current flowing through the circuit. When the pressure of the water pump is increased, the water will flow faster through the pipe. Similarly, increasing the potential difference in an electric circuit will cause electrons to flow faster and increase the current. However, the resistance in the circuit will remain constant even if the voltage and current change.

## Ohm’s Law Pie Chart

The pie chart below illustrates how the components of Ohm’s Law — Voltage (V), Current (I), and Resistance (R) — interact.

It shows that when voltage increases, current also increases in direct proportion while resistance decreases. This inverse relationship between voltage and resistance is a fundamental principle of electricity. When applied to electrical circuits, Ohm’s Law states that voltage equals the product of current and resistance.

The pie chart also reveals how the three components of Ohm’s Law are related. For instance, if voltage increases, then current will increase while resistance decreases — in other words, increased voltage requires less resistance to maintain the same current flow. The chart also shows that if resistance increases, then voltage and current must decrease proportionally.

## Calculating Electrical Power Using Ohm’s Law

Electric power refers to how fast electrical energy is changed into other forms of energy, such as heat, mechanical energy, and energy in magnetic or electric fields. The unit used to measure this power is the watt. To calculate the electrical power, one can apply Ohm’s Law by inserting the values of voltage, current, and resistance.

Formula to find power

Power is the rate at which work or energy moves. In an electrical circuit, we can figure out how much power there is by multiplying voltage and current (P = VI). We can also express the formula for power in terms of resistance (P = I^2R or P = V^2/R). This means that as voltage and current increase, power increases. But if resistance increases, then power decreases.

To use Ohm’s Law to find the power, we need to know the voltage, current and resistance in a circuit. can calculate the power by using one of these formulas: P = VI, P = I^2R or = V^2/R.

Also Check: Tables 2 to 20

## Experimental Verification of Ohm’s Law

Ohm’s Law must be verified experimentally to accurately calculate the power in an electrical circuit. To do this, a voltage and current readings are taken for different resistance values. Then, the ratio of voltage to current is compared with the theoretical value calculated using Ohm’s Law. If the two values match, the validity of Ohm’s Law is confirmed.

Ohm’s Law can be easily verified by the below experiment:

Apparatus Required:

• Resistor
• Ammeter
• Voltmeter
• Battery
• Plug Key
• Rheostat

## Limitations of Ohm’s Law

Ohm’s Law, commonly used in electrical circuits, has some limitations. Some of the main limitations observed in Ohm’s Law are:

Ohm’s Law only applies to linear electrical devices where the parameters like resistance and capacitance follow the linearity of voltage and current. For non-linear devices, Ohm’s Law cannot be applied as these elements do not follow the same linearity.

You cannot use Ohm’s Law to analyze unilateral networks because they only permit current to flow in one direction. Transistors and diodes are examples of these types of devices.

Ohm’s Law is only applicable in the steady state, which means that it cannot be used to analyze the behavior of a circuit when its parameters are changing.

## Ohm’s Law Solved Example

Example 1: A circuit has a voltage of 12 volts and a resistance of 3 ohms. Calculate the current flowing through the circuit.

Solution: Using Ohm’s Law, we can find the current: I = V/R I = 12/3 I = 4 amps

Therefore, the current flowing through the circuit is 4 amps.

Example 2 : A resistor has a resistance of 50 ohms and a current of 0.5 amps flowing through it. What is the voltage drop across the resistor?

Solution: Using Ohm’s Law, we can find the voltage drop: V = IR V = 0.5 x 50 V = 25 volts

Therefore, the voltage drop across the resistor is 25 volts.

Example 3: A circuit has a current of 2 amps flowing through it and a voltage drop of 10 volts across it. What is the resistance of the circuit?

Solution: Using Ohm’s Law, we can find the resistance: R = V/I R = 10/2 R = 5 ohms

Therefore, the resistance of the circuit is 5 ohms.

Example 4: A circuit has a resistance of 100 ohms and a voltage of 220 volts. Calculate the current flowing through the circuit.

Solution: Using Ohm’s Law, we can find the current: I = V/R I = 220/100 I = 2.2 amps

Therefore, the current flowing through the circuit is 2.2 amps.

Example 5: A resistor has a resistance of 20 ohms and a voltage drop of 50 volts across it. What is the current flowing through the resistor?

Solution: Using Ohm’s Law, we can find the current: I = V/R I = 50/20 I = 2.5 amps

Therefore, the current flowing through the resistor is 2.5 amps.

## What is a Power Triangle?

The Power Triangle is a visual representation of the relationship between electrical power, voltage, and current in an electrical circuit. It is a useful tool to calculate the power consumed by electrical devices.

### Power Triangle Formula

If the values of current and voltage are given, Then the formula for finding power is P=VI

If the values of power and voltage are given,Then the formula for finding current is I=P/V

If the values of power and current are given, Then the formula for finding voltage is V=P/I

### Power Triangle Components

There are three Components of a power triangle.

1. Horizontal Component: Horizontal component represents the voltage.
2. Vertical Component: vertical component represents the current,.
3. Hypotenuse: hypotenuse represents the power.

The angle between the voltage and current components represents the power factor, which is a measure of how efficiently electrical power is being used in the circuit.

To use the Power Triangle, you need to know at least two of the three components (voltage, current, and power) and then use the Pythagorean theorem to solve for the missing component.

## Conclusion

Ohm’s Law is a basic connection between voltage and current in an electric circuit. It states that the quotient of potential difference and electric current is unchanging for a specific component or substance. This Law has various practical uses in electrical engineering, electronics, and telecommunications. Despite its limitations, it remains a crucial resource in comprehending electric circuits.

## Frequently Asked Questions – FAQs

Georg Simon Ohm

### What Is Ohm’s Law Simple Definition?

Ohm’s Law is a fundamental principle of physics that is used to calculate the relationship between voltage, current and resistance in an electrical circuit. Specifically, Ohm’s Law states that the current flows through conductors between two points. This can be expressed mathematically as I = V/R, where I is current in amperes (A), V is the voltage in volts (V), and R is the resistance in ohms (Ω). By simple definition, Ohm’s Law is a formula that is used to calculate the relationship between voltage, current and resistance in an electrical circuit.

### What Is Ohm’s Law Class 10?

Ohm’s law in class 10 is a basic principle in physics that is used to calculate the relationship between electric current, voltage, and resistance in a circuit. According to Ohm’s Law current flowing through conductors is directly proportional to the voltage applied across it and inversely proportional to the resistance of the conductor. Ohm’s Law is a simple way to understand and analyze many electrical circuits and is an important concept to learn in class 10.

### What Are the Limitations of Ohm’s Law?

Ohm’s Law is a useful principle for understanding the many electrical circuits, voltage and electric current, but there are some limitations to its applicability. some of the main limitations of Ohm’s Law include:

• Non-ohmic materials.
• Temperature effects.
• AC circuits.
• Voltage limits.

### What Can Ohm’s Law Be Used For?

Ohm’s law is used to validate the static values of circuit components such as current voltage, Current supplies, electric current, and voltage drops.

### When Ohm’s Law Is Not Applicable?

Ohm’s law does not apply to unilateral electrical components such as diodes and transistors.

### What Is Ohm’s Law in Physics?

Ohm’s Law is a fundamental principle in physics that represents the relationship between electric current, voltage, and resistance in a circuit. According to state ohm’s law, the current flowing through conductors is directly proportional to the voltage applied across it and inversely proportional to the resistance of the conductor.

### What Is the Meaning of Ohm’s Law?

The meaning of Ohm’s Law is the basic principle that represents the relationship between electric current, voltage, and resistance in a circuit.

### When does Ohm’s law fail?

The Ohm’s law fail in all situations when analyzing the complex circuits. Here we are added some instances when Ohm’s Law fails.

• Non-linear resistors
• Time-varying fields
• High-frequency circuits
• Temperature effects

### What is the SI unit of Ohm’s law formula?

The SI unit of electric resistance is the ohm (Ω). 1 Ω = 1 V/A.

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