Lorentz Froce is a useful topic for Class 12 Physics students, especially for CBSE, NCERT, and RBSE curricula. This article, based on Chapter 4 "Moving Charges and Magnetism," includes derivations crucial for exams. It is also useful for NEET and other competitive exams.
Lorentz Force
Lorenz force is the force experienced by a charged particle moving in space where both electric and magnetic fields exist is called Lorenz force.
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| Lorentz Forde Formula |
Consider a point charge q moving with velocity v in the presence of both an electric field E and a magnetic field B. The force on this electric charge q due to both fields is given by
`\vec F = \vec F_{\text{electric}}+\vec F_{\text{mangetic}}`
`\vec F = \vec F_e + \vec F_m`
`\vec F = q \vec E + q (\vec v \times \vec B)`
`\vec F = q ( \vec E + \vec v \times \vec B )`
Where,
q = Charge of the particle,
`\vec E` = Electric Field,
`\vec v = ` Velocity of the particle,
`\vec B =` Magnetic Field,
`\vec v \times \vec B` = Cross product of the velocity and the magnetic field vectors.
This force, known as the Lorentz Force, was formulated by H. A. Lorentz based on Ampere's and other's experiments.
Components of Lorentz Force
There are two components of Lorentz force
Electric Field
The electric component of the Lorentz force, `\vec F_e = q \vec E`, acts on a charged particle.
Magnetic Component
The magnetic component, `\vec F_B = q (\vec v \times \vec B)`, depends on the particle's velocity and the magnetic field. It is zero when the particle is stationary.
The magnetic force depends on the charge q, velocity v, and magnetic field B.
For a negative charge, the force direction is opposite to that for a positive charge.
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| The direction of the magnetic force diagram |
The magnetic force acts perpendicularly to both the velocity and the magnetic field, following the right-hand rule.
Important Points
✯ Lorentz Force formula in vector form
`\vec F = q ( \vec E + \vec v \times \vec B )`
✯ The Tesla (T) is named after Nicola Tesla.
✯ A smaller unit of the magnetic field, the gauss `(1 garss = 10^{- 4} T)`, is also commonly used.
✯ The Earth's magnetic field is approximately `3.6 \times 10^{- 5} T.`
✯ The magnetic force is zero if the charge is stationary (v = 0).
Related Questions
1. What is Lorentz Force?
2. Who formulated the concept of the Lorentz Force?
3. Write the formula for the Lorentz Force.
4. What is the electric component of the Lorentz Force?
Q5. What is the magnetic component of the Lorentz Force?
6. When is the magnetic component of the Lorentz Force zero?
7. What happens to the magnetic force if the velocity and magnetic field are parallel or antiparallel?
8. What is the approximate value of the Earth's magnetic field in Tesla?
9. Under what condition is the magnetic force on a charged particle zero?
10. What is the formula of electric force?
11. What is Lorentz's force definition?
Conclusion
The Lorentz Force, formulated by H.A. Lorentz, describes the force on a charged particle moving through electric and magnetic fields. Given by `\vec F = q ( \vec E + \vec v \times \vec B )`, it combines electric and magnetic components, crucial for understanding particle dynamics in various physical contexts.
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