(i) Blu - 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.
(iii) But, Blu-ray uses a blue-violet laser to write. Hence, it is called as Blu-Ray.

(i) RISC stands for Reduced Instruction Set Computers. They have a small set of highly optimized instructions.
(ii) Complex instructions are also implemented using simpler instructions, thus reducing the size of the instruction set.
(iii) Examples of RISC processors are Intel P6, Pentium IV, AMD K6 and K7.

Word size determines the amount of RAM that can be accessed by a at one time and the total number of pins on the microprocessor. Total number of input and output pins in turn determines the architecture of the microprocessor.

Every microprocessor has an internal clock that regulates the speed at which it executes instructions. The speed at which the microprocessor executes instructions is called clock speed. Clock speed is measured in MHz (Mega Hertz) or in GHz (Giga Hertz).

(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.