Full Test 2 - EKT CSE - AFCAT MCQ

Relative velocity of one train w.r. to other

= 42 – (-30) (as both are in opposite direction)

= 72 kmph = 20 m/sec

Total distance to be covered by each train to cross other train = 120 + 80 = 200 m

Time taken by each train to cross other train = 200/20 = 10 sec

By using

Doppler’s effect is applicable to both light and sound waves. According to Doppler’s effect, whenever there is a relative motion between a source of sound and listener, the apparent frequency of sound heard by the listener is different from the actual frequency of sound emitted by the source.

Apparent frequency,

As the man can see upto 2 m, so has short sight. So he has to use concave lens to see far and focal length of that lens will be such that the image of any object will set at distance of 2 m from eye.

u = ∝,v = 2m = 200cm,f = ?
From equation of lens, 
⇒ f = 200 cm
So the power of lens, 

It is usually written as wavelength = c / frequency.

For balancing the bridge:

Isothermal process {u = f(T) only}

As temperature is constant in isothermal process so the internal energy also remains constant.

That’s why in an isothermal process the heat transfer is equal to the work transfer.

It states that the magnitude of emf induced in the coil is equal to the rate of change of flux that linkages with the coil. The flux linkage of the coil is the product of number of turns in the coil and flux associated with the coil.
Magnetic flux: ϕ_B=BAcosθwhere θ is angle between B and the normal to the plane.
Induced EMF: 

A page fault is a type of interrupt, called trap, raised by computer hardware when a running program accesses a memory page that is mapped into the virtual address space, but not actually loaded into main memory. The hardware that detects a page fault is the processor's memory management unit (MMU), while the exception handling software that handles page faults is generally a part of the operating system kernel. When handling a page fault, the operating system generally tries to make the required page accessible at the location in physical memory, or terminates the program in case of an illegal memory access.

Unshielded twisted pair is a type of cable that consists of two unshielded wires twisted around each other. Due to its low cost, UTP cabling is used extensively for local-area networks (LANs) and telephone connections.

Signed Magnitude: +0 = 0000 and -0 = 1000

One’s Complement: +0 = 0000 and -0 = 1111

Two’s Complement: +0 = 0000 and -0 = 0000

Step 1: write 7 in binary i.e 0111

For 1’s complement:

Reverse all the bits i.e 0 to 1 and 1 to 0.

For 2’s complement:

Starting from unit’s digit, whenever the 1^st ‘1’ is encountered write it as it is and then take reverse of the remaining bits. So, 0111 = 1001

Switches are network devices that operate on layer-2 of OSI model of communication. Switches are also known as intelligent hubs. Switches operate on hardware addresses to transfer data across devices connected to them. The reason switches are known as intelligent hubs is because they build address table in hardware to keep track of different hardware addresses and the port to which each hardware address is associated.

sizeof is an operator which yields the memory occupied (in bytes) by its argument.

In c, a char is always 1 byte long, an int is always 4 bytes long and a float is always 4 bytes long.

Since variable ch is char, therefore output is 1.

Database design involves 4 phases - Requirement collection & analysis phase, conceptual schema (or conceptual database), logical design phase & physical design phase.

ER models are used in conceptual Database design phase. It includes detailed description of the entity types, relationship & constraints.

A array is an ordered list of a finite number of homogenous data elements stored in a continuous memory location. It is called ordered because the elements of the array are arranged so that there is a first, second, third and so on.

Homogenous because it contains single type of data.

Data link layer is responsible for creating and recognizing fame boundaries. This is called as frame delimiting. This is accomplished by attaching special bit patterns at the beginning and end of the frame.

leading bits to identify each class are:

Class A - 0

Class B – 01

Class C - 011      

Class D - 0111

⊕ represents exclusive or in which output is high when either of inputs is high but not both inputs are high.

Truth table of A⊕B

So, 1⊕1 = 0

(A = 1; B = 1)

In computing, a nibble is a four - bit aggregation or half an octet. It is also known as half - byte. In a networking or telecommunication context, the nibble is often called a semi - octet,[6] quadbit.

Functionality of application layer are:

• Support for file transfers

• Ability to print on a network

• Electronic mail

• Electronic messaging

• Browsing the World Wide Web

The Banker’s algorithm is a resources allocation and deadlock avoids deadlock by denying or postponing the request if it determines that accepting the requests could put system in an unsafe states.

The ASCII table has 128 characters, with values from 0 through 127.

Thus, 7 bits are sufficient to represent a character in ASCII; however, most computers typically reserve 1 byte, (8 bits), for an ASCII character.

One byte allows a numeric range from 0 through 255 which leaves room for growth in the size of the character set, or for a sign bit.

Consequently, a character data type may optionally represent signed values;

However, for now, we will assume that character data types are unsigned, i.e. positive integer values, in the range 0-127.

Syntax

expression-1 ? expression-2 : expression-3

In the above symbol expression-1 is condition and expression-2 and expression-3 will be either value or variable or statement or any mathematical expression. If condition will be true expression-2 will be execute otherwise expression-3 will be executed.

Well known ports are those from O through 1023. 80 is the well known port for http used in the world wide web.

In IEEE 802.5, the token passing scheme is used in place of CSMA/CD on a ring topology LAN.
Token Ring local area network (LAN) technology is a communications protocol for local area networks. It uses a special three-byte frame called a "token" that travels around a logical "ring" of workstations or servers. This token passing is a channel access method providing fair access for all stations, and eliminating the collisions of contention-based access methods.
Introduced by IBM in 1984, it was then standardized with protocol IEEE 802.5 and was fairly successful, particularly in corporate environments, but gradually eclipsed by the later versions of Ethernet.

f(x) = x²e^-x

f^I(x) = x²(-e^-x) + e^-x × 2x

⇒ f^I(x) = e^-x(2x-x²)

Putting f^I(x) = 0

⇒ e^-x (2x – x²) = 0

x(2-x) = 0

⇒ x = 0 or x = 2

∴ x = 0 & x = 2 are the stationary points

f^II(x) = e^-x(2 - 2x) + (2x – x²) (-e^-x)

= e^-x (x² – 4x + 2)

At x = 0, f^II(0) = 2 > 0

∴ At x = 2, we have maximum value of f(x).

Auxiliary equation is
m²+5m+6=0

If λ₁,λ₂,λ₃ are the Eigen values of A then Eigen values of Adj A are