What are the physical characteristics of magnetic disks?  

Ans: A magnetic disk is a circular plate or platter of plastic or metal that is coated with magnetizable material like iron-oxide on both sides. Data are recorded on the disk surface in the type of tiny invisible magnetized spots (denoting 1s) or non-magnetized spots (denoting 0s). A conducting coil, named as Head, carries out the job of reading and writing on the surface of magnetic disk. Usually, the head remains stationary whereas the disk rotates below it for reading or writing operation. The surface of the disk is categorized into a number of concentric circles known as tracks. Number of tracks alters from disk to disk. Each track is further sub categorized into sectors. Every sector of a disk is assigned a unique number. Each sector having similar capacity.