Solved examples of using the Right-Hand Rule for Magnetic Force

📚 Quick Study Guide

• 🧲 The Right-Hand Rule helps determine the direction of the magnetic force on a moving charge in a magnetic field.
• 🖐️ Point your fingers in the direction of the velocity ($v$) of the positive charge.
• 👆 Curl your fingers in the direction of the magnetic field ($B$).
• 👍 Your thumb points in the direction of the magnetic force ($F$).
• 💡 For a negative charge, the force is in the *opposite* direction of your thumb.
• 🔢 The magnitude of the magnetic force is given by $F = qvB\sin(\theta)$, where $q$ is the charge, $v$ is the velocity, $B$ is the magnetic field strength, and $\theta$ is the angle between $v$ and $B$.
• 🧭 If the velocity and magnetic field are parallel ($\theta = 0$) or antiparallel ($\theta = 180^{\circ}$), then the magnetic force is zero.

Practice Quiz

1. What does the Right-Hand Rule determine?
1. The direction of the electric field.
2. The direction of the gravitational force.
3. The direction of the magnetic force on a moving charge.
4. The direction of the electric potential.
2. A positive charge moves to the right in a magnetic field pointing upwards. What is the direction of the magnetic force on the charge?
1. Upwards
2. Downwards
3. Into the page
4. Out of the page
3. A negative charge moves to the left in a magnetic field pointing downwards. What is the direction of the magnetic force on the charge?
1. Upwards
2. Downwards
3. Into the page
4. Out of the page
4. A proton is moving north in a magnetic field pointing east. In what direction is the magnetic force on the proton?
1. North
2. East
3. Upwards
4. Downwards
5. An electron is moving south in a magnetic field pointing west. In what direction is the magnetic force on the electron?
1. North
2. East
3. Upwards
4. Downwards
6. If a charge moves parallel to a magnetic field, what is the magnitude of the magnetic force on the charge?
1. Maximum
2. Minimum
3. Equal to the electric force
4. Undefined
7. What is the formula for the magnitude of the magnetic force on a moving charge?
1. $F = qvB\cos(\theta)$
2. $F = qvB\sin(\theta)$
3. $F = qE$
4. $F = ma$