Positively charged alpha particles move in a circular path with a radius of about 4.0 cm under the influence of a magnetic field with a strength equal to about 1.0 T. What magnitude and direction for an applied electrical field would cause these alpha particles' trajectory to become linear? [Hint: The mass of an alpha particle = 6.644 × 10^-27 kg, the charge of an alpha particle = +2 ×1.602 × 10^-19 C.]

• A. The magnitude of the electric field = 1.9 × 10⁶ V / m,The electric field points radially away from the center.
• B. The magnitude of the electric field = 1.9 × 10⁶ V / m,The electric field radially towards the center.
• C. The magnitude of the electric field = 2.9 × 10⁶ V / m,The electric field points radially away from the center.
• D. The magnitude of the electric field = 2.9 × 10⁶ V / m,The electric field points radially towards the center.