i) Four point charges encompass the similar magnitude of 3.4 x 10-12 C and are fixed to the corners of a square which is 8.5 cm on a side. Three of the charges are positive and one is negative. Find out the magnitude of the total electric field which exists at the center of the square.
ii) The electronic flash attachment for a camera includes a capacitor for storing the energy employed to produce the flash. In one such unit, the potential difference among the plates of an 1100-μF capacitor is 300 V. (a) Find out the energy which is used to produce the flash in this unit. (b) Supposing that the flash lasts for 4.1 ms, determine the effective power or "wattage" of the flash.