Aptitude Test Problems in Physics Science for Everyone by S Krotov ( PDFDrive.com )

3. Electricity and Magnetism^95

guides directed at an angle a to the horizon-

tal and separated by a distance b. The guides

are connected at the bottom through an

uncharged capacitor of capacitance C, and

the entire system is placed in an upward

Fig. 108

magnetic field of induction B. At the ini-

tial moment, the jumper is held at a distance

/ from the foot of the "hump" (Fig. 108).

Determine the time t in which the re-

leased jumper reaches the foot of the hump.

What will be its velocity vf at the foot?

The resistance of the guides and the jumper

should be neglected.

3.54*. A quadratic undeformable supercon-

ducting loop of mass m and side a lies in a

horizontal plane in a nonuniform magnetic

field whose induction varies in space ac-

cording to the law Bx = —ax, B y = 0,

Bz = az + Bo (Fig. 109). The inductance

of the loop is L. At the initial moment, the

centre of the loop coincides with the ori-

gin 0, and its sides are parallel to the x-

and y-axes. The current in the loop is zero,

and it is released.