UGC NET CS 2017 Jan – III

Question 1

Which of the following is an interrupt according to temporal relationship with system clock ?

• A. Maskable interrupt
• B. Periodic interrupt
• C. Division by zero
• D. Synchronous interrupt

Answer: (D)

According to temporal relationship with system clock we classify interrupt in two ways: 1- Synchronous: The source of interrupt is in phase to the system clock is called synchronous interrupt. In other words interrupts which are dependent on the system clock. Example: timer service that uses the system clock. 2- Asynchronous: If the interrupts are independent or not in phase to the system clock is called asynchronous interrupt. So, option (D) is correct. For more information on interrupt Refer:Different types of interrupt levels

Question 2

Which of the following is incorrect for virtual memory?

• A. Large programs can be written
• B. More I/O is required
• C. More addressable memory available
• D. Faster and easy swapping of process

Answer: (B)

1. We can write large program when we have memory extension.
2. Less I/O requirement in case of virtual memory.
3. More addressable memory available with virtual memory
4. Faster and easy swapping of process with the help of page replacement policy in virtual memory.
So, option (B) is correct. For more information on virtual memory Refer:Virtual Memory | Operating System

Question 3

The general configuration of the micro-programmed control unit is given below: What are blocks B and C in the diagram respectively?

• A. Block address register and cache memory
• B. Control address register and control memory
• C. Branch register and cache memory
• D. Control address register and random access memory

Answer: (B)

The general configuration of the micro-programmed control unit: So, option (B) is correct.

Question 4

Match the following :

• A. (1)
• B. (2)
• C. (3)
• D. (4)

Answer: (A)

1. In Implied Addressing Mode location of operand specified implicitly in the definition of instruction
2. In Immediate Addressing Mode location of operand specified in the register.
3. In Register Addressing Mode location of operand in registers which are in CPU
4. In Register Indirect Addressing Mode register specifies the address of the operand

So, Option (A) is correct.

Question 5

In 8085 microprocessor, the digit 5 indicates that the microprocessor needs:

• A. –5 volts, +5 volts supply
• B. +5 volts supply only
• C. –5 volts supply only
• D. 5 MHz clock

Answer: (B)

In 8085 microprocessor, the digit 5 indicates that the microprocessor needs +5 volts supply only. So, option (B) is correct.

Question 6

In 8085, which of the following performs : load register pair immediate operation?

• A. LDAX rp
• B. LHLD addr
• C. LXI rp, data
• D. INX rp

Answer: (C)

LDAX - Load accumulator indirect( This instruction copies the contents of that memory location into the accumulator. ) LHLD - Load H and L register direct ( This instruction loads the contents of the 16- bit memory location into the H and L register pair. ) LXI - Load register pair immediate( The instruction loads 16-bit data in the register pair designated in the operand.) INX - Increment register pair by 1.( It will increment the register value by 1.) So, option (C) is correct.

Question 7

Consider following schedules involving two transactions: S1 : r1(X); r1(Y); r2(X); r2(Y); w2(Y); w1(X) S2 : r1(X); r2(X); r2(Y); w2(Y); r1(Y); w1(X) Which of the following statement is true?

• A. Both S1 and S2 are conflict serializable.
• B. S1 is conflict serializable and S2 is not conflict serializable.
• C. S1 is not conflict serializable and S2 is conflict serializable.
• D. Both S1 and S2 are not conflict serializable.

Answer: (C)

S1 is not conflict serializable and S2 is conflict serializable. So, option (C) is correct.

Question 8

Which one is correct w.r.t. RDBMS ?

• A. primary key ⊆ super key ⊆ candidate key
• B. primary key ⊆ candidate key ⊆ super key
• C. super key ⊆ candidate key ⊆ primary key
• D. super key ⊆ primary key ⊆ candidate key

Answer: (B)

primary key ⊆ candidate key ⊆ super key in RDBMS For more information Refer:DBMS | Keys in Relational Model (Candidate, Super, Primary, Alternate and Foreign) Option (B) is correct.

Question 9

Let pk(R) denotes primary key of relation R. A many-to-one relationship that exists between two relations R₁ and R₂ can be expressed as follows :

• A. pk(R₂) → pk(R₁)
• B. pk(R₁) → pk(R₂)
• C. pk(R₂) → R₁ ∩ R₂
• D. pk(R₁) → R₁ ∩ R₂

Answer: (B)

Question 10

For a database relation R(A, B, C, D) where the domains of A, B, C and D include only atomic values, only the following functional dependencies and those that can be inferred from them are : A → C B → D The relation R is in _______.

• A. First normal form but not in second normal form.
• B. Both in first normal form as well as in second normal form.
• C. Second normal form but not in third normal form.
• D. Both in second normal form as well as in third normal form.

Answer: (A)

A relation is in first normal form if every attribute in that relation is single valued attribute. It is in 1NF. {A,B} are prime attribtes and {C,D} are non-prime attribute. A⁺ = {A,C} B⁺ = {B,D} {A,B}⁺ = {A,B,C,D} so AB is the key. But A⁺ = {A,C} B⁺ = {B,D} makes it partial dependency. So, this relation is not in 2NF. So, option (A) is correct.