Materi Kemagnetan Kelas 9 (Part-4) Latihan Soal Gaya Lorentz

Summary

This tutorial teaches how to solve physics problems related to Lorentz force. The lesson covers various scenarios involving a current-carrying conductor in a magnetic field, calculating the resulting force, and determining unknown variables such as magnetic field strength, current, and length. The script includes step-by-step explanations of applying the Lorentz force formula (F = BIL), with examples to guide learners through different types of questions. Key concepts such as unit conversions and vector directions for forces are also covered, helping students master the calculations and the concepts behind them.

Takeaways

• 😀 The script focuses on solving problems related to Lorentz force and the factors affecting it, including current, magnetic field, and wire length.
• 😀 The first question demonstrates how to calculate the Lorentz force using the formula: F = B * I * L, where B is the magnetic field, I is the current, and L is the wire length.
• 😀 The script explains the process of converting units, such as from milliampere to ampere, to ensure correct calculations.
• 😀 A simple approach to solving these problems involves breaking down the math, such as dividing values and simplifying equations.
• 😀 The second question explores how to calculate the magnetic field (B) given the Lorentz force, current, and wire length using the formula B = F / (I * L).
• 😀 The script emphasizes the importance of unit conversions when working with scientific measurements, such as converting cm to meters.
• 😀 For the third problem, the script demonstrates how to calculate the current (I) from known values of Lorentz force, magnetic field, and wire length.
• 😀 When solving problems involving Lorentz force, the script suggests simplifying equations by canceling out common factors, such as 10's in both the numerator and denominator.
• 😀 In a problem about calculating the length of a wire, the script shows how to use the formula L = F / (B * I), and simplify it by eliminating common factors.
• 😀 The script also covers the concept of the right-hand rule to determine the direction of the Lorentz force based on the directions of current and magnetic field.
• 😀 Overall, the script encourages practicing different approaches to solving Lorentz force problems and emphasizes the importance of understanding the underlying physics principles.

Q & A

What is the formula to calculate the Lorentz force?

The formula to calculate the Lorentz force is F = B * I * L, where F is the force (in Newtons), B is the magnetic field strength (in Tesla), I is the current (in Amperes), and L is the length of the conductor (in meters).

What is the first step to solve a Lorentz force problem?

The first step is to identify the known values from the problem, such as the length of the wire (L), the current (I), and the magnetic field strength (B). Then, use the formula F = B * I * L to find the force.

How do you convert milliampere to ampere?

To convert milliampere (mA) to ampere (A), divide the value in milliampere by 1000. For example, 3 mA is equal to 3/1000 A, which is 0.003 A.

What does the right-hand rule help determine in a Lorentz force problem?

The right-hand rule helps determine the direction of the Lorentz force. By pointing your thumb in the direction of the current and your fingers in the direction of the magnetic field, your palm will face the direction of the force.

In the first problem, if the length of the wire is 5 meters, the current is 0.5 amperes, and the magnetic field is 12 Tesla, what is the Lorentz force?

Using the formula F = B * I * L, we get F = 12 * 0.5 * 5 = 30 N. Therefore, the Lorentz force is 30 Newtons.

How do you calculate the magnetic field strength given the force, current, and length of the wire?

To calculate the magnetic field strength (B), use the formula B = F / (I * L), where F is the force, I is the current, and L is the length of the wire.

In the second problem, if the Lorentz force is 6 N, the current is 3 mA, and the length of the wire is 2 meters, what is the magnetic field strength?

First, convert 3 mA to amperes (0.003 A). Then, using the formula B = F / (I * L), we get B = 6 / (0.003 * 2) = 1000 Tesla.

How do you solve for the current when the Lorentz force, magnetic field, and length of the wire are known?

To solve for the current (I), use the formula I = F / (B * L), where F is the force, B is the magnetic field strength, and L is the length of the wire.

In the third problem, if the force is 12 N, the magnetic field is 3 Tesla, and the length of the wire is 80 cm, what is the current?

First, convert 80 cm to meters (0.8 m). Then, using the formula I = F / (B * L), we get I = 12 / (3 * 0.8) = 5 A.

How do you calculate the length of a wire when the Lorentz force, magnetic field, and current are known?

To calculate the length (L), use the formula L = F / (B * I), where F is the force, B is the magnetic field strength, and I is the current.