Question Discussion & Solution

Saw is used for cutting wood.

Similarly, Scythe is used for cutting Grass.

The correct answer is option 1.

Concept:

Weak entity set :

A weak entity set is an entity set that does not contain sufficient attributes to uniquely identify its entities. In other words, a primary key does not exist for a weak entity set. However, it contains a partial key called a discriminator. Discriminators can identify a group of entities from the entity set.

ER diagram:

This ER diagram illustrates key information about the book, including entities such as author, Publisher, books, and Edition. It allows for understanding the relationships between entities.

Author:

For an author, the book dealer might want to keep track of the name (first, middle, and last), date of birth, and date of death.​

Publisher: 

For a Publisher, the book dealer might want to keep track of the phone, name, and address.

Book:

For a book, the book dealer might want to keep track of the id, title, and date.

Edition:

For an edition, the book dealer might want to keep track of the name and the total number of copies.

Relation ER diagram,

• The author can write a number of books and each number of books has many numbers of authors. So it has many to many relationships.
• The book can publish at most one publisher and each number of publishers has many numbers books. So it has many to one relationship.
• The book can has atmost one edition and each number edition has many numbers of books. So it has many to one relationship.

The ER diagram,

Here Edition is a weak entity because it can not have candidate key attributes.​

Hence the correct answer is Edition.

The correct answer is In 1829.

• In order to prevent the practice of Sati, in 1829 it was first banned under the "Bengal Sati Regulation".

Key Points

• The Bengal Sati Regulation
  • ​The Bengal Sati Regulation was passed on December 4, 1829, here is all you should definitely know about the practice of Sati.
  • The Bengal Sati Regulation which banned the Sati practice in all jurisdictions of British India was passed on December 4, 1829, by the then Governor-General Lord William Bentinck.

Additional Information

• About Sati practice
  • Sati was a historical Hindu practice, in which a widow sacrifices herself by sitting atop her deceased husband's funeral pyre.
  • The extent to which sati was practised in history is not known with clarity.
  • However, during the early modern Mughal period, it was notably associated with the elite Hindu Rajput clan.

Concept:

• The laws dealing with ideal gases naturally called ideal gas laws, and the laws determined in the seventeenth century by Boyle's observational work and in the eighteenth century by Charles.
• The Boyles Law states that the gas pressure is inversely proportional to the gas volume for a given mass of gas stored at a constant temperature.
• Charles Law states that the gas volume is directly proportional to the gas temperature for a given fixed mass of gas stored at a constant pressure. 
• An ideal gas is a gas that follows the equation:

PV = nRT at all temperatures and pressure, where P = Pressure of the ideal gas. V = Volume of the ideal gas n = Amount of ideal gas measured in terms of moles 

R = Universal gas constant T = Temperature

Mole Concept -

•  The quantity one mole of a substance signifies 6.022 × 1023 number of particles of that substance which may be atoms, molecules, or ions.
• The quantity is a universal constant like Dozen, Gross, etc., and is known as Avogadro number, denoted by NA. after the scientist Amedeo Avogadro.
• Examples- In one mole of H2, there are 6.022 × 1023 molecules of hydrogen, and the number of atoms is 2 × 6.022 × 1023, as one molecule of hydrogen contains two-atom each.
• The mass of one mole of a substance is called its Molar Mass (M) or Atomic mass expressed in grams.
• The volume occupied by a mole of gas is 22.4 L at NTP, called its Molar Volume.
• The no. of moles (n) is calculated as =

The number of particles / Avogadro’s number.

To summarise, we can say, 

Calculation:

• The molar mass of 1 mole of H₂SO₄ is =

2 × 1 + 32 + 4 × 16 = 98g

• The molar mass of 1 mole of Silver, Ag is its molecular mass 108g.
• The molar mass of CO₂ is = 12 + 2× 16 = 44g.
• 44g of CO₂ means one mole.
• 1 mole of Oxygen weighs 16 + 16 = 32g.
• Hence, the highest mass is of 1 mole of Ag.