Electronics and Communication Engineering - Digital Electronics

46. 

The number of digits in hexadecimal system

A. 15
B. 16
C. 10
D. 8

Answer: Option B

Explanation:

It has 16 digits 0 to 15.


47. 

Which of these is the most recent display device?

A. LED
B. LCD
C. VF
D. (a) and (c)

Answer: Option C

Explanation:

VF display can operate at very low voltages, has low power consumption and very long life.


48. 

A NOR gate has 3 inputs A, B, C. For which combination of inputs is output HIGH

A. A = B = C = 0
B. A = B = C = 1
C. A = B = 1 and C = 0
D. A = C = 1 and B = 0

Answer: Option A

Explanation:

NOR gate gives High output when all inputs are Low.


49. 

In 2's complement form, - 2 is

A. 1011
B. 1110
C. 1100
D. 1010

Answer: Option B

Explanation:

A = 1110,

A = 0001,

A + 1 = 0001 + 1 = 0010 = 2

Therefore A = -2.


50. 

The Boolean function/implemented in the figure using two I/P multiplexers is

A. ABC + ABC
B. ABC + AB C
C. ABC + ABC
D. ABC + AB C

Answer: Option A

Explanation:

when B = 1, f1 = ABC

B = 0, f2 = ABC

f = f1 + f2 = ABC + ABC.


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