Computer Fundamentals Multiple choice Questions and Answers on CPU & Control Unit for Freshers

1. Brain of computer is ____________

a) Control unit
b) Arithmetic and Logic unit
c) Central Processing Unit
d) Memory

Answer: c

Explanation: The CPU is referred to as the brain of a computer.
It consists of a control unit and the arithmetic and logic unit. It is responsible for performing all the processes and operations.

2. Control Unit acts as the central nervous system of the computer.

a) True
b) False

Answer: a

Explanation: The control unit is referred to as the central nervous system because it selects and interprets the instructions and coordinates execution.

3. What does MBR stand for?

a) Main Buffer Register
b) Memory Buffer Routine
c) Main Buffer Routine
d) Memory Buffer Register

Answer: d

Explanation: The binary subtraction 0 – 1 gives the result 1.
A borrow of 1 is although generated and is removed from the next higher column.

4. In the instruction ADD A, B, the answer gets stored in ___________

a) B
b) A
c) Buffer
d) C

Answer: b

Explanation: In any instruction of the form ADD A, B; the answer gets stored in the A register. The format is: ADD Destination, Source.

5. What does PC stand for?

a) Program Changer
b) Program Counter
c) Performance Counter
d) Performance Changer

Answer: b

Explanation: The Program counter contains the address of the next instruction which is to be fetched by the control unit.
All other options are invalid.

6. Which of the following holds the last instruction fetched?

a) PC
b) MAR
c) MBR
d) IR

Answer: d

Explanation: The IR which stands for the instruction register contains the last instruction fetched.
All the others options are registers which are used for the fetch operation.

7. The portion of the processor which contains the hardware required to fetch the operations is _______

a) Datapath
b) Processor
c) Control
d) Output unit

Answer: a

Explanation: The datapath contains the hardware required to fetch the operations. The control tells the data path what needs to be done.

8. Causing the CPU to step through a series of micro operations is called _________

a) Execution
b) Runtime
c) Sequencing
d) Pipelining

Answer: c

Explanation: Sequencing is the process of causing the CPU to step through a series of micro operations. Execution causes the performance of each micro operation.

9. The functions of execution and sequencing are performed by using ______________

a) Input Signals
b) Output Signals
c) Control Signals
d) CPU

Answer: c

Explanation: Sequencing followed by the process of execution is performed by the Control signals. Sequencing is traversing each and every operation whereas execution causes the performance of each operation.

10. What does D in the D-flip flop stand for?

a) Digital
b) Direct
c) Delay
d) Durable

Answer: c

Explanation: In the hardwired control unit, the delay element method uses D-flip flop which causes a delay. Since, in the delay element method, there must be a finite time gap between the 2 steps.