1. In a system design the electrons are accelerated from restthrough a potential difference of 250 V. The electrons travel alonga curved path because of the magnetic force exerted on them, andthe radius of the path is measured to be 5 cm long. If the magneticfield is perpendicular to the beam what is the linear speed of theelectrons, what is the angular speed of the electrons and what isthe magnitude of the magnetic field in this system,respectively?

A. 9.4 x 106 m/s, 188 x 106 rad/s, 107.5 x 10-6 T
B. 2.4 x 103 m/s, 2.61 x 105 rad/s, 13.6 x 10-4 T
C. 6.8 x 107 m/s, 1.82 x 107 rad/s, 22.7 x 10-3 T
D. 1.2 x 107 m/s, 214 x 107 rad/s, 9.4 x 10-4 T

2. What is the direction of magnetic force created by a movingparticle?
A. Same direction with the velocity of the particle
B. Same direction with the magnetic field
C. Direction of the vectoral product of charge of the particle andthe magnetic field
D. Direction of the vectoral product of velocity of the particleand the magnetic field

3.

What is the magnetic force created by a current carrying wire?(Please choose two corrert answers)

A. Different than zero on a closed loop  
B. Zero on a closed loop  
C. Depends on the angle between the length vector and magneticfield lines  
D. Depends on the angle between the length vector and velocityvector

4.

What did Oersted discovered?

A. Magnetic force created by a closed loop
B. Magnetic force of a charged particle
C. Compass needle is deflected by a current carrying wire
D. Magnetism of a charged particle