15. A drift tube is made of a conductive cylinder, with inner radius R_b, and a thin conductive wire of radius R_a at the center of the cylinder. Apply a voltage V between the wire and the cylinder, what is the resulting charge density (charge per unit length) on the wire? (A) (B) (C) (D) (E)

3. A solid sphere of mass m and radius r moves along a track with a circular loop of radius R1 as shown in following picture. It is released at height h. Assuming that the track has no friction, the ball thereforeslides down without rotation. Do not ignore the finite size of the sphere, what is the minimal value of h such that the sphere remains on the track at all times? (A) 2.5R − 1.5r (B) 2R − r (C) 2.5R (D) 2R + r (E) 2R − 1.5r

15. A drift tube is made of a conductive cylinder, with inner radius R_b, and a thin conductive wire of radius R_a at the center of the cylinder. Apply a voltage V between the wire and the cylinder, what is the resulting charge density (charge per unit length) on the wire?
(A)
(B)
(C)
(D)
(E)

相關試題

相關試卷