A proton, moving in negative y-direction in a magnetic field , experiences a force of magnitude F, acting in the negative x direction.
a) What is the direction of the magnetic field producing force?
b) Does your answer change if the word proton is replaced by electron?
I get a little confused when doing the right hand rule but for a) I get Negative z direction and for be it will be the opposite so I get positive z direction. The book says it's the opposite but I don't know how to get that. I point my thumb to the left and then my middle finger to the negative x direction that will be into the page and my index is pointing downwards. So don't know how to get the real answer...
To determine the direction of the magnetic field producing the force on a charged particle, you can use the right-hand rule. Here's how:
1. Extend your right hand with your thumb pointing in the direction of the particle's velocity (negative y-direction in this case).
2. Now, curl your fingers toward the negative x-direction. Your fingers will represent the direction of the magnetic field lines.
3. The direction your thumb is pointing is the direction of the force experienced by the charged particle (negative x-direction in this case).
So based on the right-hand rule, the force on the proton is in the negative x-direction. Now let's consider the second part of the question.
If the word proton is replaced by electron, the answer does change. The force experienced by an electron moving in the negative y-direction in a magnetic field would be in the opposite direction to that experienced by a proton. This is because electrons have a negative charge, while protons have a positive charge.
Using the same right-hand rule as before, if the electron is moving in the negative y-direction, you would point your thumb in that direction. Then, when you curl your fingers toward the negative x-direction, you find that your index finger will point upwards. Therefore, the force on the electron would be in the positive z-direction.
So, the correct answer is:
a) The direction of the magnetic field producing the force on the proton is in the negative z-direction.
b) The answer does change if the word proton is replaced by electron. The direction of the magnetic field producing the force on the electron is in the positive z-direction.