GATE CS 1998

Question 11

Regarding the power of recognition of languages, which of the following statement is false?

• The non-deterministic finite state automata are equivalent to deterministic finite state automata.
• Non-deterministic pushdown automata is equivalent to deterministic pushdown automata.
• Non-deterministic Turing machines are equivalent to deterministic Turing machines.
• Multi-tape Turing machines are equivalent to Single-tape Turing machines.

Question 12

The string 1101 does not belong to the set represented by

• 110* (0+1)
• 1(0+1)* 101
• (10)* (01)* (00+11)*
• (00+(11)*0)*

Question 13

What happens when a bit-string is XORed with itself n-times as shown: [ B⊕ (B⊕ (B⊕ (B........ n times) ]  

• complements when n is even
• complements when n is odd
• divides by 2^n always
• remains unchanged when n is even

Question 14

A multiplexer with a 4-bit data select input is a

• 4:1 multiplexor

• 2:1 multiplexor

• 16:1 multiplexor

• 8:1 multiplexor

Question 15

The threshold level for logic 1 in the TTL family is

• any voltage above 2.5 V
• any voltage between 0.8 V and 5.0 V
• any voltage below 5.0 V
• any voltage below Vcc but above 2.8 V

Question 16

In serial communications employing 8 data bits, a parity bit and 2 stop bits, the minimum band rate required to sustain a transfer rate of 300 characters per second is

• 2400 band
• 19200 band
• 4800 band
• 1200 band

Question 17

The octal representation of an integer is (342)₈. If this were to be treated as an eight bit integer in an 8085 based computer, its decimal equivalent is

• 226
• -98
• 76
• -30

Question 18

Which of the following devices should get higher priority in assigning interrupts?

• Hard disk
• Printer
• Keyboard
• Floppy disk

Question 19

Which of the following is true?

• Unless enabled, a CPU will not be able to process interrupts.
• Loop instructions cannot be interrupted till they complete.
• A processor checks for interrupts before executing a new instruction.
• Only level triggered interrupts are possible in microprocessors.

Question 20

Which of the following algorithm design technique is used in finding all pairs of shortest distances in a graph?

• Dynamic programming
• Backtracking
• Greedy
• Divide and Conquer