CLASS IV
CHAPTER 3
THE SYSTEM UNIT
A. Write full forms of the following: (pg. 30)
1. CPU – Central Processing Unit
2. CU – Control Unit
3. ALU – Arithmetic and Logic Unit
4. RAM – Random Access Memory
5. ROM – Read Only Memory
6. CD – Compact Disk
7. DVD - Digital Versatile Disk
B. Answer the following questions. (pg. 31)
1. What is a system unit?
Ans. A system unit is a metal case that acts as a guard of the
electronic components of the computer.
2. Name some components inside the system unit.
Ans. 1. Motherboard 2. CPU 3. Hard disk drive
4. RAM 5. ROM 6. CD – ROM drive
3. What is the function of the CPU?
Ans. CPU is known as the brain of the computer as it controls
all the working of the computer.
4. What is CU and ALU ?
Ans. (1) CU (Control unit) directs and manages most of the
operations of the computer.
(2) ALU (Arithmetic and logic unit) performs all the
arithmetical and logical operations of the computer.
