Ohmsche Gesetz (URI) mit Beispielen | Physik | Lehrerschmidt

Summary

In this video, the concept of Ohm's Law is explained, highlighting the relationship between voltage, current, and resistance. Georg Simon Ohm's discovery in 1826 reveals that voltage and current are directly proportional. The video provides clear examples to calculate resistance using the formulas: R = U/I, U = R*I, and I = U/R. Through practical problems, viewers learn to compute voltage, current, and resistance in different electrical circuits. The video is designed to make the understanding of Ohm's Law accessible, with easy-to-follow calculations and real-life examples.

Takeaways

• 😀 Ohm's Law describes the relationship between voltage (U), current (I), and resistance (R) in an electrical circuit.
• 😀 Ohm's Law was discovered by Georg Simon Ohm in 1826, and it shows that voltage and current are directly proportional to each other.
• 😀 The mathematical expression of Ohm's Law is: R = U / I, U = R * I, and I = U / R.
• 😀 Voltage (U) is measured in volts (V), current (I) in amperes (A), and resistance (R) in ohms (Ω).
• 😀 The unit for resistance, Ohm (Ω), is equivalent to 1 volt per ampere.
• 😀 Doubling the voltage in a circuit will double the current, and halving the voltage will halve the current, assuming resistance remains constant.
• 😀 In a voltage-current diagram, the relationship between voltage and current is represented as a straight line.
• 😀 To calculate resistance (R), use the formula: R = U / I.
• 😀 To calculate voltage (U), use the formula: U = R * I.
• 😀 To calculate current (I), use the formula: I = U / R.
• 😀 Practical examples are provided to demonstrate how to apply Ohm's Law to real-world problems, such as calculating resistance, voltage, and current.

Q & A

What does Ohm's Law describe?

Ohm's Law describes the relationship between electrical voltage (U), current (I), and resistance (R) in a circuit. It states that the current flowing through a conductor is directly proportional to the voltage and inversely proportional to the resistance.

Who discovered Ohm's Law and when?

Ohm's Law was discovered by Georg Simon Ohm, a German physicist, in 1826.

How are voltage and current related in a circuit according to Ohm's Law?

In a circuit, voltage and current are directly proportional. This means that if the voltage is doubled, the current also doubles. Similarly, if the voltage is halved, the current is halved.

What is the mathematical formula for Ohm's Law?

The mathematical formula for Ohm's Law is: R = U / I, where R is the resistance, U is the voltage, and I is the current. The formulas can also be rearranged to U = R * I and I = U / R.

What is the unit of electrical resistance and how is it derived?

The unit of electrical resistance is the Ohm (Ω), which is derived from the relationship 1 Volt per 1 Ampere. It is represented by the symbol Ω.

How can the resistance of a circuit be calculated if the voltage and current are known?

The resistance (R) can be calculated using the formula R = U / I, where U is the voltage and I is the current.

If the voltage in a circuit is 20V and the current is 4A, what is the resistance?

Using Ohm's Law, R = U / I. Substituting the values, R = 20V / 4A = 5Ω.

How do you calculate the voltage if the resistance and current are given?

The voltage (U) can be calculated using the formula U = R * I, where R is the resistance and I is the current.

In an example where the resistance is 80Ω and the current is 10A, what is the voltage?

Using the formula U = R * I, we substitute the values: U = 80Ω * 10A = 800V.

How can the current be calculated if the voltage and resistance are known?

The current (I) can be calculated using the formula I = U / R, where U is the voltage and R is the resistance.

If a household device has a resistance of 50Ω and is connected to a 230V power supply, what is the current?

Using the formula I = U / R, we substitute the values: I = 230V / 50Ω = 4.6A.