9. A charged particle is moving in a uniform magnetic field. Its initial velocity is perpendicular to the magnetic field. Which one of the following statements is TRUE? (A) The particle's kinetic energy is changing with time. (B) The radius of the particle's circular path is independent of its speed. (C) The cyclotron frequency of the particle's circular motion is independent of its speed. (D) The cyclotron frequency of the particle's circular motion is independent of its mass. (E) The cyclotron frequency of the particle's circular motion is independent of the magnetic field.

8. A series RC circuit is connected across an ideal DC voltage source through an open switch. The switch is closed at time t = 0 sec. Which of the following statements regarding the circuit is correct? (A) The potential differences across the resistor and the capacitor are always equal. (B) The potential difference across the resistor is always greater than that across the capacitor. (C) The potential difference across the capacitor is always greater than that across the resistor. (D) Once the capacitor is essentially fully charged, the potential difference across the capacitor becomes zero. (E) Once the capacitor is essentially fully charged, the potential difference across the resistor becomes zero.

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