A beam ofions passes continuously through a uniform magnetic field of strength To- The (lpoint) direction of the beam and the field are perpendicular to each other. When the strength of the magnetic field is increased to 2To, how will the particles be affected?

a. They will travel at the same speed but in a circular arc of larger radius.
b. They will travel at an increased speed in a circular arc of smaller radius.
c. They will travel at the same speed but in a circular arc of smaller radius.
d. They will travel at an increased speed in a circular arc of the same radius.