Question

• An electron, at rest, is accelerated through region 1, which has a 5000 V potential difference. It then enters region 2 where there is only a uniform magnetic field and it undergoes uniform circular motion (in a plane) of radius 0.954 mm. After subtending half a circle, the electron exits region 2, traveling in the opposite direction it was before entering region 2. (a) Draw a physical representation of this situation, complete with the direction of the electric and magnetic fields in the two regions. (b) Is the initial point of the electron in region 1 necessarily at zero electric potential? (c) Is the electric field from the potential difference in region 1 necessarily uniform? (d) What is the orientation of the magnetic field in region 2, relative to the plane of motion? (e) What is the speed of the electron when it exits region 2? (f) What is the strength of the magnetic field in region 2?

Answer 1

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(e) FUTom electuro static e nngy potumtial emngy comsuvation kinatic emungy omvunt im to will That is AV elicturom of the bu the whuy -19 2 x 16x1o 2 5000 9.IXI31 CT 4 19 3 x L0 cr

(f) Radius of th cincula path of electu1om im V1giom-is th marte fiald Aturength whuu B bu -31 X 4.193 x LO 9.1イ10 B 3 x 0.954 X Lo -19 1.6x10 T B = o. 2 4-9