7. A parallel-plate capacitor is connected to a battery at constant potential difference, and allowed to charge up. Put a slab of dielectric material between the plates of the capacitor while the capacitor is still connected to the battery. Which one of the following is TRUE? (A) The energy stored in the capacitor has decreased (B) The energy stored in the capacitor has no changed. (C) The voltage across the capacitor has decreased. (D) The charge on the capacitor has decreased. (E) The charge on the capacitor has increased.

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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