Digital Electronics and Microprocessors - MCQS

Note: We have tried to upload as much as we can, all the question and answers might be shuffled - Please find the answer below each question, some answers might be wrong please review on the last date(some answers might be changed) if you find any of the answer is wrong please comment down below. 

Question 1

DMA interface unit eliminates the need to use CPU registers to transfer data From

(A)  MAR to MBR (B) MBR to MAR (C) I/O units to memory (D) Memory to I/O units

Select one:

a. c

b. a

c. b

d. d

Correct Answer: D

Question 2

Out of the 4 operations listed below , which do you find not to be taking place during the execution cycle?

(A) ALU performs the arithmetic & logical operation.

(B) Effective address is calculated.

(C) Next instruction is fetched.

(D) Branch address is calculated & Branching conditions are checked.

Select one:

a. a

b. c

c. b

d. d

Correct Answer: D

Question 3

For an 8086 find the physical memory address of the data stored in following memory locations

DS: BX   = 1000h:1200h

A. 11200 H   B. 13000H   C.  2200H     D. 22000H

Select one:

a. c

b. d

c. a

d. b

Correct Answer: C

Question 4

How many (128 x 8) RAM chips are needed to provide a memory capacity of

2048 X 16 ?

(A)  8 (B) 16 (C) 24 (D) 32

Select one:

a. a

b. c

c. b

d. d

Correct Answer: D

Question 5

1.If In addition of two signed numbers, represented in 2' s complement, A is the carry in to the sign bit position and B is the carry out of the Sign bit position then what logic will show an overflow condition?

(A)  A. B = 0 (B) A = 0 (C) A xor B = 1 (D) A + B = 1

Select one:

a. d

b. b

c. c

d. a

Correct Answer: C

Question 6

1.How many flip-flops are required for a divide by 32 counter?

A.3 B. 4 C.32 D.5

Select one:

a. a

b. b

c. d

d. c

Correct Answer: C

Question 7

A JK flip-flop can be implemented using D flip-flop connected such that

(A)D=JQ’+K’Q (B) D=J'Q+KQ (C)D=JQ+K'Q' (D) D=JQ+KQ'

Select one:

a. c

b. b

c. d

d. a

Correct Answer: D

Question 8

What will be the ending addresses of a 64 K Byte memory segment as in 8086 if the segment register contains AB11H

A. DCBF0H  B. ABBA0H  C. BB10F H  D. AB110H

Select one:

a. c

b. b

c. a

d. d

Correct Answer: C

Question 9

How does the CMP B instruction affect the flags? chose the best option

A. Only sign flag affected   B. Only Carry flag affected   C. All flags affected   D. None of the flags affected

Select one:

a. d

b. b

c. c

d. a

Correct Answer: C

Question 10

For 8086 What will be the content of Accumulator and the carry flag after executing the instruction RAR if the accumulator and carry flag contained  10100111 & 0 respectively before executing the instruction

A.11010011 & 1         B. 01010011 & 0

C.01010011 & 1         D.  11010011 & 0

Select one:

a. d

b. c

c. b

d. a

Correct Answer: B

Question 11

What are the basic steps for the execution of an instruction?

A.Fetch, Decode, Execute         B. Decode, Fetch, Execute

C.Decode, Execute, Fetch         D. Execute Decode, Fetch,

Select one:

a. c

b. a

c. d

d. b

Correct Answer: B

Question 12

For 8086  What is the length of the instruction POP D

A.4 Byte        B. 3 Byte

C.1 Byte        D. 2 Byte

Select one:

a. a

b. d

c. b

d. c

Correct Answer: D

Question 13

What register is used for reading status of  Flag Registers?

A. Flag Register        B. Status Register

C. Control register     D. Buffer Register

Select one:

a. a

b. b

c. d

d. c

Correct Answer: B

Question 14

IMUL is

A.Signed  Multiplication         B. Unsigned  Multiplication

C.Multiplication                 D. Inverse Multiplication

Select one:

a. b

b. d

c. c

d. a

Correct Answer: D