Question Discussion & Solution

The correct answer is to Correct the eye defects.

• Lenses are widely used in spectacle to correct eye defects.
• There are three common defects of vision that can be corrected with the help of suitable spherical lenses (convex lenses or concave lenses).
• Myopia is also known as Short-sightedness or nearsightedness.
  • Due to this defect, the person cannot see the distant objects clearly but he/she can see the nearby objects clearly.
  • The far point of the eye having myopia is less than infinity.
  • The defect is caused due to the high converging power of eye-lens or due to the eyeball being too long.
  • It can be corrected by making use of spectacles containing concave lenses.
• Hypermetropia is also known as Long-sightedness or farsightedness.
  • Due to this defect, the person cannot see the nearby objects clearly but he/she can see the distant objects clearly.
  • The near point of a hypermetropic eye is more than 25 centimetres away.
  • The defect is caused due to the low converging power of eye-lens or due to the eye-ball being too short.
  • It can be corrected by making use of spectacles containing convex lenses.
• Presbyopia is a vision disease caused mostly in old age.
  • The ciliary muscles become weak and the eye-lens become rigid and the eye loses its power of accommodation in old age in this vision defect.
  • In Presbyopia the person cannot see the nearby objects clearly due to loss of power of accommodation of the eye.
  • The near point of the old person having presbyopia gradually reduces and becomes much more than 25 centimetres away.
  • It can be corrected by making use of spectacles containing convex lenses.
• A person suffering from both Myopia and Hypermetropia uses spectacles having bifocal lenses in which the upper part consists of a concave lens to correct myopia and the lower part consists of a convex lens to correct hypermetropia.

The correct answer is 14-Nov-2012.

• The POSCO Act was enacted on 14-Nov-2012.

Key Points

• The POSCO Act,2012:
  • The act is an acronym Protection Of Children from Sexual Offences Act.
  • The act was enacted on June 19, 2012.
  • It was enforced on November 14, 2012.
  • The act was enacted to protect children from offences of sexual assault, sexual harassment, and pornography and safeguard the interest and well-being of children.
  • According to the act, the definition of a child is any person below eighteen years of age.
  • It also defines different forms of sexual abuse which include penetrative and non-penetrative assault as well as sexual harassment and pornography.

The correct answer is A) 4, B) 2, C) 1, D) 3.

Key Points

• Sodium - It can be simply cut with knife as a result of Sodium has one negatron in its valence shell. Being the primary part of that amount, it is giant size.
• Mercury is liquid at temperature. A heavy, silvery d-block component, mercury is that the solely metal that's liquid at customary conditions for temperature and pressure.
• Silver is that the sensible conductor of electricity as a result of it contains the next variety of movable atoms (free electrons). For a fabric to be an honest conductor, the electricity more experienced it should be able to move the electrons.
• Lead being metal may be a dangerous conductor of electricity and warmth. Compared to alternative metals, lead may be a poor conductor of warmth whereas gold, silver, Pt square measure sensible conductors of warmth.

Concept:

The nucleus of the Cell

• The cell is the basic building block of all living beings. 
• The nucleus is the special structure located generally at the center of the cell. 
• The nuclear membrane separates the cytoplasm from the nucleus. 
• The nucleus contains a central part called nucleolus and chromosomes. 
• Chromosomes and nucleolus coexist in the nucleus. Chromosomes are not present in the nucleolus.

Chromosomes and Genes

• Chromosomes carry genes and help in the inheritance or transfer of characters from the parents to their children. 
• The chromosomes can be seen only when the cell divides.
• The credit for the discovery of chromosomes goes to Strasburger as he first described the chromosome structure seen in the nucleus during cell division.
• Usually, chromosomes are rod-shaped, elongated, or dot-like in shape with sizes varying from 0.5 to 32 micrometer.
• In humans, 23pairs of chromosomes are found i.e. 46 in numbers.

Conclusion:

• Chromosomes are present in the nucleus of the cell. So, all the given options are wrong. 
• The correct option is None of these.

Additional Information

• The cell membrane is also known as the plasma membrane. 
  • It is a porous structure that allows the exit and entry of certain materials according to its requirement. 
  • This is the major function of the cell membrane. 
• The cytoplasm is between the cell and the nucleus.
  • Cell organelles like mitochondria, Golgi bodies, ribosomes, etc. are present in the cytoplasm. 
  • Mitochondria is called the powerhouse of cells and is responsible for cellular respiration. 
  • vacuole is open space between cell which is used for storing food. 
• Plastids are double-membrane organelles found in the plant cell. They contain pigments that help the plant in photosynthesis.

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.