UGC NET Computer Science 2024 Previous Year Questions (PYQs) – Page 1 of 20

Nyquist Sampling Theorem states:

Sampling frequency must be at least twice the maximum frequency present in the signal.

$ f_s \ge 2f_{max} $

Dual is obtained by interchanging:

$+$ ↔ $\cdot$

$0$ ↔ $1$

Applying dual rule:

A → III

B → IV

C → II

D → I

Tokens are the smallest meaningful units of a program.

Break the statement:

for | i | in | range | ( | begin | : | end | : | step | ) | :

Tokens:

for

i

in

range

(

begin

:

end

:

step

)

:

Total tokens = 12

From the diagrams:

• Both machines are deterministic (each state has exactly one transition for each input symbol).

• The first machine has states A and B with transitions on a and b.

• The second machine has states A, B, C, but the accepted language behavior matches the first machine.

Both machines accept the same language, even though the number of states differs.

Thus they are equivalent machines.

Complement of fuzzy set:

$\mu_{A'}(x) = 1 - \mu_A(x)$

Compute:

$x_1$: $1 - 0.3 = 0.7$

$x_2$: $1 - 0.7 = 0.3$

$x_3$: $1 - 0.4 = 0.6$

Thus,

$A' = {(x_1,0.7),(x_2,0.3),(x_3,0.6)}$

Interrupt Service Routine (ISR) steps:

Save processor registers → C

Check which device raised interrupt → D

Service the device → B

Restore processor registers → E

Re-enable interrupt facility → A

Correct sequence:

C, D, B, E, A

Number of spanning trees:

For complete graph:

$\tau(K_n)=n^{n-2}$

A: $K_3 = 3^{1} = 3$

B: $K_4 = 4^{2} = 16$

For complete bipartite graph:

$\tau(K_{m,n}) = m^{n-1} n^{m-1}$

C: $K_{2,2} = 2^{1} \times 2^{1} = 4$

For cycle graph:

$\tau(C_n)=n$

D: $C_5 = 5$

Thus:

A = 3

C = 4

D = 5

B = 16

Increasing order:

A, C, D, B

Standard I/O techniques are:

• Programmed I/O

• Interrupt-driven I/O

• Direct Memory Access (DMA)

Rotational I/O and Channelized I/O are not standard CPU I/O techniques.

Thus:

A, B, D are correct.

Common properties of social networks:

• Scale-free degree distribution → True

• Small world property → True

• Short average path length → True

However, most social networks are not necessarily directed; many are modeled as undirected networks.

Thus the statement that is not a common property is:

A grammar is ambiguous if a string generated by it has more than one parse tree.

Equivalent definitions:

• More than one leftmost derivation

• More than one rightmost derivation

Thus the correct statements are:

B and C.