Conceptual Physics

Section 9 - Interactive problem: charged particle moving in a B field

9.1 Use the information given in the interactive problem in this section to answer the following questions. Test your answers

using the simulation. (a) How many angles between 0° and 180°, inclusive, will result in a force of 0 N? (b) What angle in that

range will give a force equal to 0 N? (If there is more than one, give the largest.) (c) What angle between 0° and 180°,

inclusive, will maximize the resulting force?

(a) i. 0

ii. 1

iii. 2

iv. 3

v. 4

(b) ° (c) °

Section 10 - Determining the strength of a magnetic field

10.1 A proton is moving at 2.00×10^5 m/s and begins to circle at a radius of 5.00eí3 m. What is the strength of the perpendicular

magnetic field acting on the proton?

T

10.2 A proton travels with a speed of 8.34×10^5 m/s at an angle of 32.3° with the direction of a magnetic field. The field exerts a

force of 3.00×10í^17 N on the proton. What is the strength of the field?

T

10.3 A charged body has a charge of 3.33 μC. It is moving with a speed of 8320 m/s at an angle of 42.0° with a uniform magnetic

field. The field exerts a force of 0.0117 N on the body. What is the strength of the magnetic field?

T

10.4 A television screen is illuminated using a beam of electrons traveling at 7.50×10^6 m/s in a 1.75×10í^2 T magnetic field. If an

electron is moving in the positive x direction and the magnetic field is oriented 55.0° from the z axis in the first quadrant of the

xz plane, what are the (a) magnitude and (b) direction of the acceleration of the electron?

(a) m/s^2

(b) i. Positive x

ii. Positive y

iii. Positive z

iv. Negative x

v. Negative y

vi. Negative z

10.5 A uranium atom is ionized seven times, losing seven electrons in the process. Its resulting mass is 3.90×10í^25 kg and it is

given a kinetic energy of 3000 eV. If it circles in a magnetic field at a radius of 3.00 m, what is the strength of the magnetic

field?

T

10.6 An alpha particle (m = 6.68×10í^27 kg, q = 3.20×10í^19 C) is moving perpendicularly to a uniform magnetic field at a speed of

7.88×10^6 m/s. Because of the force exerted on it by the magnetic field, it is accelerating at 5.67×10^12 m/s^2. What is the

strength of the magnetic field?

T

Section 11 - Interactive problem: B field strength and particle motion

11.1 Use the information given in the interactive problem in this section with an initial speed of 400 m/s to find the B field strength

needed to achieve the desired amount of force. Test your answer using the simulation.

T

Section 12 - Physics at work: velocity selector

12.1 The electric field in a velocity selector is generated by two parallel plates separated by 5.00 cm with a potential difference of

90.0 V. If the magnetic field is 6.00eí2 T, at what speed will particles pass through undeflected?

m/s

12.2 A velocity selector is tuned to let charges with a speed of 325 m/s pass through. If the strength of the magnetic field is

0.250 T, what is the strength of the electric field?

N/C

(^532) Copyright 2007 Kinetic Books Co. Chapter 28 Problems