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

94 Aptitude Test Problems in Physics

Determine the radius r of the circle in

which the ball moves if the thread is always

stretched.

3.51. A metal ball of radius r moves at a

constant velocity v in a uniform magnetic

field of induction B.

Indicate the points on the ball the poten-

tial difference between which has the maxi-

mum value Aymax• Find this value, as-

suming that the direction of velocity forms

an angle a with the direction of the mag-

netic induction.

3.52. A direct current flowing through the

winding of a long cylindrical solenoid of

radius ft produces in it a uniform magnetic

field of induction B. An electron flies into

the solenoid along the radius between its

turns (at right angles to the solenoid axis)

Fig. 107

at a velocity v (Fig. 107). After a certain

time, the electron deflected by the magnetic

field leaves the solenoid.

Determine the time t during which the

electron moves in the solenoid.

3.53. A metal jumper of mass m can slide

without friction along two parallel metal