Two conducting carbon rods of diameter 1.5 cm are connected to a 15.0 V battery. The circular faces of the rods are parallel and separated by 3.0 mm, forming a capacitor. The rods are disconnected from the battery when the current stops flowing. After disconnection, insulators are used to alter the rod separation to 4.0 mm. Calculate the charge and potential difference between electrodes after the separation.

A student conducted an experiment that aimed to determine the influence of different operating parameters on the potential difference across the plates of a parallel-plate capacitor. The student coupled a 10.0 μF capacitor made of two parallel circular plates, each of radius r, and separated by a distance d, to a 15 V voltage source and let it charge completely before disconnecting the source. Assume no action changes the charge on the plates. i) Determine the reading on a voltmeter connected to the charged capacitor. ii) The student increases the distance between the two plates to 5d, what does the voltmeter read? iii) Find the voltmeter's reading when the plate radius is stretched to 3r and the distance remains d.

An electrical technician applied a potential difference of V = 35.0 V between the plates of an air-filled parallel-plate capacitor. The area of the plates is 7.20 cm². The technician determined that the magnitude of the charge stored on each plate equals 300.0 pC. i) Find the distance (d) separating the two plates. ii) The technician then tripled the spacing between the plates. Find the new value of the potential difference (V_new) that will charge each plate to 300.0 pC.

Using two metal plates, a physics student builds a parallel-plate capacitor. The gap between the two plates is set at exactly 4.0 mm apart, and each holds an equal but opposite charge with a magnitude of 120 nC. The medium between them is a vacuum, while they experience an electric field having an intensity of 7.0 × 10⁶ V/m. Determine (a) the voltage difference across them, (b) the surface area per plate, and (c) the capacitor's capacitance.