Question Discussion & Solution

OSI Model

• OSI stands for Open System Interconnection is a reference model that describes how information from a software application in one computer moves through a physical medium to the software application in another computer.
• OSI consists of seven layers, and each layer performs a particular network function.
• OSI model was developed by the International Organization for Standardization (ISO) in 1984, and it is now considered as an architectural model for inter-computer communications.

There are seven OSI layers. Each layer has different functions. A list of seven layers are given below:

1) Physical Layer: 

• The main functionality of the physical layer is to transmit the individual bits from one node to another node.
• It is the lowest layer of the OSI model.

2) Data-Link Layer: 

• This layer is responsible for the error-free transfer of data frames.
• It defines the format of the data on the network.
• It provides reliable and efficient communication between two or more devices.

3) Network Layer: 

• It is a layer 3 that manages device addressing, tracks the location of devices on the network.
• It determines the best path to move data from source to destination based on the network conditions, the priority of service, and other factors.
• Logical Addressing and Routing are functions of the Network Layer.

4) Transport Layer: 

• The Transport layer is a Layer 4 ensures that messages are transmitted in the order in which they are sent and there is no duplication of data.
• The main responsibility of the transport layer is to transfer the data completely.

5) Session Layer:

• The Session layer is used to establish, maintain, and synchronizes the interaction between communicating devices.

​6) Presentation Layer:

• It acts as a data translator for a network.
• This layer is a part of the operating system that converts the data from one presentation format to another format.

7) Application Layer: 

• An application layer serves as a window for users and application processes to access network service.
• This layer provides network services to the end-users.
• HTTP is an application layer protocol designed within the framework of the Internet protocol suite. Its definition presumes an underlying and reliable transport layer protocol, and Transmission Control Protocol (TCP) is commonly used.

​Thus, HTTP is an application layer in the OSI Model of Networking.

In a certain code language, 'BENJAMIN' is written as 'NIMAJNEB'. First letter of the word moves last and second letter of the word moves second last place and so on.

Similarly, 'POVERTY' written in that code language as 

POVERTY is written as YTREVOP.

Hence, "YTREVOP" is the correct answer.

Given that Mars, Planets, Celestial Bodies.

All Mars situated in Planets and all Planets are situated in Celestial Bodies.

The Venn diagram given bellow-

Hence, option 1 is the correct answer.

Words that can be formed using A, E, L and T are

LATE, TALE, LEAT, TEAL, TAEL, TELA

The correct answer is Ammeter.

Key Points

• Ammeter
  • An ammeter is an instrument that is used to measure the current in the circuit.
  • It measures either direct or alternating electric current, in amperes (A).
  • It has a set of coils with very low resistance and inductive reactance.
  • This allows for very low impedance, the force that opposes electric current.

Additional Information

• Wattmeter
  • The wattmeter is an instrument for measuring the electric active power in watts of any given circuit.
  • Electromagnetic wattmeters are used for the measurement of utility frequency and audio frequency power; other types are required for radio frequency measurements.
• Hygrometer
  • Hygrometer instrument used in meteorological science to measure the humidity or amount of water vapour in the air.
• Pyrometer
  • A pyrometer is a type of remote-sensing thermometer used to measure the temperature of distant objects