Answer: D) All of the above Explanation: Magnetic disk is a kind of data storage device. Storage capacity of magnetic disk depends on  1. tracks per inch of surface 2. bits per inch of tracks 3. disk pack in disk surface   It can be shown as ::

Answer: C) Stealth virus Explanation:

Answer: A) DRAM Explanation: Memory refresh is the process of periodically reading information from an area of computer memory and immediately rewriting the read information to the same area without modification, for the purpose of preserving the information. Memory refresh is a background maintenance process required during the operation of semiconductor dynamic random-access memory (DRAM), the most widely used type of computer memory.

Answer: D) All of the above Explanation: A computer has two types of memory. 1. Non-volatile and 2. Volatile.   Volatile memory is computer memory that requires power to maintain the stored information. * It is a temporary memeory which cannot contain information permanently. Example :: RAM or Random Access Memory   Non-volatile memory is computer memory that can retain the stored information even when not powered. * It is a permanent memory in which data is stored in permanently. Examples :: Hard disc, ROM, Floppy discs, Magnetic tape,...

Answer: A) DPI Explanation: Dots per inch (DPI, or dpi) is a measure of spatial printing or video or image scanner dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch (2.54 cm).

Answer: C) 8 bit Explanation: Word length refers to the number of bits processed by a computer's CPU in one go. These days, typically 32 bits or 64 bits are used. Data bus size, instruction size, address size are usually multiples of the word size.

Answer: C) Ctrl + Z Explanation: For undo the action or last action [Ctrl + Z] is used.