QUESTION What would happen to the instantaneous trajectory of the orbiting proto
ID: 1492162 • Letter: Q
Question
QUESTION What would happen to the instantaneous trajectory of the orbiting proton if the solenoid were suddenly re-oriented so its axis becomes vertical? (Select all that apply.)
(a)The proton would stop moving.
(b) The proton, as one possibility, could move upward out of the solenoid.
(c)The proton would move in a plane oriented at about 45° away from horizontal.
(d)The proton, as one possibility, could keep moving in a circle in the horizontal plane.
(e)It depends on the proton's instantaneous position and direction of motion in its orbit when the change occurs.
PRACTICE IT
Use the worked example above to help you solve this problem. A certain solenoid consists of 138 turns of wire and has a length of 10.1 cm.
(a) Find the magnitude of the magnetic field inside the solenoid when it carries a current of0.620 A.
? T
(b) What is the momentum of a proton orbiting inside the solenoid in a circle with a radius of0.023 m? The axis of the solenoid is perpendicular to the plane of the orbit.
? kg · m/s
(c) Approximately how much wire would be needed to build this solenoid? Assume the solenoid's radius is 6.19 cm.
? m
EXERCISEHINTS: GETTING STARTED
Suppose you have a 31.6 m length of copper wire. If the wire is wrapped into a solenoid 0.240 m long and having a radius of 0.0449 m, how strong is the resulting magnetic field in its center when the current is 12.6 A?
B = T
Explanation / Answer
b,d and e are true.
a is false because the proton will not stop moving.
d is also true. The proton could start out moving in a 45 degree plane, but it will end up forming a spiral going straight up (or down) with the angle of the spiral at 45 degrees (like a spiral stair case).