(i) Arithmetic operations are the mathematical operations on data like add, subtract etc.
(ii) Logical operations are the operations on binary Boolean data like AND, OR, NOT.

(i) Address Bus
(ii) Data Bus
(iii) Control Bus

(i) Address Bus
(ii) Control Bus
(iii) Data Bus

The Program Counter (PC) is a special register in the CPU which always keeps the  address of the next instruction to be executed.

A command which is given to a computer to perform an operation on data is called an instruction

A Microprocessor's performance depends on the following characteristics:
(a) Clock speed
(b) Instruction set
(c) Word size

(i) BIu - Ray disc was developed to enable recording, rewriting and playback of high-definition video as well as storing large amount of data.
(ii) DVD uses a red laser to read and write data. But, Blu-ray uses a blue-violet laser to write. Hence, it is called as Blu-Ray.

(i) The microprocessor which is an Integrated Circuit. Microprocessors were first introduced in early 1970s. The first general purpose microprocessor, 4004 was developed by Intel Inc.
(ii) The microprocessor is a programmable multipurpose silicon chip. It is driven by clock pulses. It accepts input as a binary data and after processing, it provides the output data as per the instructions stored in the memory.

The microprocessor is made up on main units. They are:
(i) Arithmetic and Logic unit (ALU): To perform arithmetic and logical instructions based on computer instructions.
(ii) Control unit : To control the overall operations of the computer through signals.
(iii) Registers (Internal Memory): They are used to hold the instruction and data for the execution of the processor.

The various types of ports are given below
Serial Port : To connect the external devices, found in old computers.
Parallel Port : To connect the printers found in old computers.
USB Ports : To connect external devices like cameras, scanners, mobile phones external hard disks and printers to the computer.

Hard disk:
(i) Hard disk is a magnetic disk on which you can store data. The hard disk has the stacked arrangement of disks accessed by a pair of heads for each of the disks.
(ii) The hard disks come with a single or double-sided disk.
Compact Disk (CD):

(i) A CD or CD-ROM is made from 1.2 millimetres thick, polycarbonate plastic material. A thin layer of aluminium or gold is applied to the surface.
(ii) CD data is represented as tiny indentations known as "pits", encoded in a spiral track moulded into the top of the polycarbonate layer. The areas between pits are known as "lands".
(iii) A motor within the CD player rotates the disk. The capacity of an ordinary CD- ROM is 700MB.
Digital Versatile Disc (DVD):

(i) A DVD (Digital Versatile Disc or Digital Video Disc) is an optical disc capable of storing up to 4.7 GB of data, more than six times what a CD can hold.
(ii) DVDs are often used to store movies at a better quality. Like CDs, DVDs are read with a laser. The disc can have one or two sides, and one or two layers of data per side; the number of sides and layers determines how much it can hold.
(iii) A 12 em diameter disc with single sided, single layer has 4.7 GB capacity, whereas the single sided, double layer has 8.5 GB capacity.
(iv) The 8 em DVD has 1.5 GB capacity. The capacity of a DVD-ROM can be visually determined by noting the number of data sides of the disc. Double-layered sides- are usually gold-coloured, while single-layered sides are usually silver-coloured, like a CD.

Read-only memory (ROM):
(i) Read only memory refers to special memory in a computer with pre-recorded data at manufacturing time which cannot be modified. The stored programs that start the computer and perform diagnostics are available in ROMs. ROM stores critical programs such as the program that boots the computer. Once the data has been written onto a ROM chip, it cannot be modified or removed and can only be read. ROM retains its contents even when the computer is. turned off. So, ROM is called as a non-volatile memory.
(ii) Once the data has been written onto a ROM chip, it cannot be modified or removed and can only be read. ROM retains its contents even when the computer is turned off. So, ROM is called as a non-volatile memory.
Programmable Read-Only Memory (PROM) :
(i) Programmable read-only memory is also a nonvolatile memory on which data can be written only once. Once a program has been written onto a PROM, it remains there forever.
(ii) Unlike the main memory, PROMs retain their contents even when the computer is turned off.
(iii) The PROM differs from ROM. PROM is manufactured as a blank memory, whereas a ROM is programmed during the manufacturing process itself. PROM programmer or a PROM burner is used to write data to a PROM chip. The process of programming a PROM is called burning the PROM.
Erasable Programmable Read-Only Memory (EPROM):
(i) Erasable Programmable Read-Only Memory is a special type of memory which serves as a PROM, but the content can be erased using ultraviolet rays.
(ii) EPROM retains its contents until it is exposed to ultraviolet light. The ultraviolet light clears its contents, making it possible to reprogram the memory.
(iii) An EPROM differs from a PROM. PROM can be written only once and cannot be erased.
(vi) EPROMs are used widely in personal computers because they enable the manufacturer to change the contents of the PROM to replace with updated versions or erase the contents before the computer is delivered. Electrically
Electrically Erasable Programmable Read-Only Memory (EEPROM):
(i) Electrically Erasable Programmable Read-Only Memory is a special type of PROM that can be erased by exposing it to an electrical charge.
(ii) Like other types of PROM, EEPROM retains its contents even when the power is turned off. Comparing with all other types of ROM,. EEPROM is slower in performance.