Question

The figure below shows the path of a proton (mass mp) as it passes through two regions of space (labeled 1 and 2) containing uniform magnetic fields of magnitudes B1 and B2, respectively. Both fields are oriented perpendicular to the page. The proton’s path in each region is a semi-circle of radius R1 and R2, respectively. In answering the questions that follow, make sure you defend each of your answers with a well-reasoned argument.

Region 1 Region 2

Q3. Does the proton move faster in one region than the other? Why or why not?

Q4. Is the magnetic field stronger in one region than the other? If so, which magnetic field isstronger and how can you tell?

Q5. What are the directions of the two magnetic fields?

Q6. Does the proton spend more time in region 1 or region 2?

Q7. If we replaced the proton with an electron (mass me=5.44×10–4mp)   while leaving the rest ofthe experiment the same (i.e., same initial velocity, same magnetic fields, same starting point,etc.), how would the path followed by the electron be different?

Help would be much apprciated :)

Answer 1

Solution: The radius of the proton's path in semicircle region is given by, nv Bg Here, m is the mass of the proton, B is the uniform magnetic field, g is the charge of the particle, and v is the velocity of the proton. Question 3 The magnetic force is always perpendicular to the velocity of the particle. Since the velocity of the particle is constant in the uniform magnetic field, so that the proton will move with same Hence the proton speed will not change while moving from uniform magnetic field, so its speed will be same.