DIGITAL ELECTRONICS MCQS PART 06

DIGITAL ELECTRONICS MCQS PART 06

1. Using complement method negative numbers can also be subtracted.
In a positive logic system, logic state 1 corresponds to
(A)positive voltage    
(B)  higher voltage level
(C)  zero voltage level    
(D)  lower voltage level
Ans: B

2.  We decide two voltages levels for positive digital logic. Higher voltage represents logic 1 & a lower voltage represents logic 0. The commercially available 8-input multiplexer integrated circuit in the TTL family is
(A) 7495.    
(B) 74153.
(C) 74154.    
(D) 74151.
Ans: B
Explanation: MUX integrated circuit in TTL is 74153.

3. CMOS circuits are extensively used for ON-chip computers mainly because of their extremely
(A)low power dissipation.
(B)  high noise immunity.
(C)  large packing density.
(D)  low cost.
Ans: C
Explanation: Because CMOS circuits have large packing density.

4.The MSI chip 7474 is
(A) Dual edge triggered JK flip-flop (TTL).
(B)Dual edge triggered D flip-flop (CMOS).
(C)Dual edge triggered D flip-flop (TTL).
(D) Dual edge triggered JK flip-flop (CMOS).
Ans: C
Explanation: MSI chip 7474 dual edge triggered D Flip-Flop.

5. Which of the following memories stores the most number of bits
(A)a 5M× 8 memory.    
(B)  a 1M × 16 memory.
(C) a 5M × 4 memory.    
(D)  a 1M ×12 memory.
Ans: A
Explanation: 5Mx8 = 5 x 220 x 8 = 40M (max)

6. The process of entering data into a ROM is called
(A)burning in the ROM    
(B) programming the ROM
(C) changing the ROM    
(D) charging the ROM
Ans: B
Explanation: The process of entering data into ROM is known as programming the ROM.

7. When the set of input data to an even parity generator is 0111, the output will be
(A) 1    
(B) 0  
(C) Unpredictable  
(D)  Depends on the previous input
Ans: B
Explanation: In even parity generator  if number of 1 is odd then output will be zero.

8. The number 140 in octal is equivalent to
(A)  (96)10     
(B)  (86)10     
(C)  (90)10     
(D)  none of these
Ans: A
Explanation: (140)8 = (96)10
1 x 8^2 + 4 x 8 + 0x 1 = 64 + 32 = 96

9. The NOR gate output will be low if the two inputs are
(A) 00    
(B) 01     
(C) 10    
(D) 11
(E) B,C,and D
Ans: E
Explanation: O/P is low if any of the I/P is high

10.Which of the following is the fastest logic?
(A)ECL    
(B) TTL   
(C) CMOS    
(D) LSI
Ans: A