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• The electric field between the plates is
directed downward.
The force on a negative particle will therefore by upward, so that (b) [5pt] The electric force can be canceled for this specific velocity by turning on a const ant
magnetic field, allowing a particle with charge
and speed to pass between the plates
undeflected. (This device is called a velocity selector.) What is the magnitude and direction of
the required magnetic field?
so the righthand rule imples that a magnetic field into the page, in the
– direction, will give a downward magnetic force which can cancel the electric field if
the magnitude is adjusted correctly. This will occur when
so that (c) [5pt] If this magnetic field is constant throughout the entire region surrounding the plates,
the electron will follow a curved trajectory after emerging from the velocity selector. Suppose
this trajectory has a radius of 29.4 cm. What is the mass of the unknown particle?
The particle will follow uniform circular motion with a centripetal force of magnitude
so that Solving for the mass gives The particle is a muon, which is similar to an electron, but 200 times heavier, and unstable. 6 6. [15pt] An solenoid contains 640 turns of wire, is 8.00 cm in length, and has a radius of 0.54
cm.
(a) [5pt] What is the magnitude and direction of the magnetic field inside the solenoid if the
current is
A? For the direction, use the coordinate system shown below.
The magnetic field points to the left, with magnitude
where
cm
turns per
meter. Thus, 8.00 cm 640 turns (b) [5pt] How much energy is in the magnetic field of the solenoid? Alternatively, with giving the same result. (c) [5pt] Suppose a short coil of radius 1.00 cm and 42 turns is wrapped about the center of the
solenoid as shown. If the cu...
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This document was uploaded on 03/09/2014 for the course PHYS 222 at Ohio Northern University.
 Spring '12
 ScottYost
 Physics

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