A beam of monochromatic light with a wavelength of 650 nm passes through a diffraction grating with slits 2500 nm apart. How many spots are observed on a large screen placed a small distance in front of the diffraction grating? A. 1 B. 3 C. 5 D. 6 E. 7

Consider a file currently consisting of 200 blocks. assume that the file control block (and the index block in the case of indexed allocation) is already in memory. calculate how many disk i/o operations are required for contiguous, linked, and indexed (single-level) allocation strategies, for each of the conditions listed below. in the contiguous-allocation case, assume that there is not room to grow at the beginning but there is room to grow at the end. also assume that the block information to be added is stored in memory.