A calliper is a device used to measure the distance between two opposing sides of an object. It can be as simple as a compass with inward or outward-facing points. First the tips of the calliper are adjusted to fit across the points to be measured and the calliper is then removed and the distance between the tips is measured using a ruler. 

The modern Vernier calliper was invented by Joseph R. Brown in 1851. It was the first practical tool for exact measurements that could be sold at an affordable price to ordinary machinists.   The Vernier Calliper consists of a main scale fitted with a jaw at one end. Another jaw, containing the vernier scale, moves over the main scale. When the two jaws are in contact, the zero of the main scale and the zero of the Vernier scale should coincide. If both the zeros do not coincide, there will be a positive or negative zero error. 

Parts of a Vernier Caliper

1.Main Scale

The main scale consists of a steel metallic strip graduated in centimeters at one edge and in inches at the other edge . It carries the inner and outer measuring jaws. When the two jaws are in contact, the zero of the main scale and the zero of the Vernier scale should coincide. If both the zeros do not coincide, there will be a positive or negative zero error.

Economics agents are those who take Economic decisions. In microeconomics there are Individual economic agents and at macro level there are institutional Economic agents who take Economic decisions.

The last sign of physical contact between the author and the grand mother is when the author decided to go abroad for his higher studies. she came to leave him at the railway station she didnt talk or show any emotion. she silently kissed his forehead and when he cherished the moist imprint as perhaps the last sign of physical contact between them.

The term ‘trade receivables’ is the amount receivable for sale of goods or services performed in the ordinary course of business operation. It is the sum of debtors and bills receivable.  

1. Debtor: A debtor is a person who receives a benefit without paying money immediately but liable to pay in future within a particular period of time.
2. Bills receivable: Bill receivable is an exchange bill accepted by the debtor for the amount which will be received on a specified date. It is included in trade receivables because bill receivable replaces a debtor.

Insurable interest is defined as the reasonable concern of a person to obtain insurance for any individual or property against unforeseen events such as death, losses, etc.

A molecule is the smallest unit (particle) of a compound having the physical and chemical properties of that compound. This does not mean that molecules can not be broken down into smaller parts, e.g. the atoms from which they are formed or the fragments of the molecule, each consisting of several atoms or parts of atoms.

A molecule is defined as the smallest unit of a compound that contains the chemical properties of the compound. Molecules are made up of groups of atoms. Describing the structure of an atom, an atom is also sub-divided into smaller units. Proton, electrons, and neutrons are sub-particles of an atom. The protons and neutrons are contained inside the nucleus of the atom and electrons revolve around the nucleus.

An essential aspect of perfect competition is the absence of any monopolistic element. These are the three essential features of perfect competition:

1. The number of buyers and sellers in the market is very large. These buyers and sellers compete among themselves. Due to the large number, no buyer or seller influences the demand or supply in the market.
2. The commodity sold or bought is homogeneous. In other words, goods produced by different firms are identical in nature.
3. Firms can enter or exit the market freely.

These are the three essential features of perfect competition:

1. The number of buyers and sellers in the market is very large. These buyers and sellers compete among themselves. Due to the large number, no buyer or seller influences the demand or supply in the market.
2. The commodity sold or bought is homogeneous. In other words, goods produced by different firms are identical in nature.
3. Firms can enter or exit the market freely.

alveolar air- the amount of air present in the alvioli after insperation
inspired air- the total amont of air inspired during inspiration

• After Muhammad’s death in 632 AD political authority was transferred to the Umma with no established principle of succession.
• This created opportunities for innovations but also caused deep divisions among the Muslims.
• The biggest innovation was the creation of the institution of caliphate, in which the leader of the community (amir al-muminin) became the deputy (khalifa) of the Prophet.
• The twin objectives of the caliphate were to retain control over the tribes constituting the umma and to raise resources for the state.
• The main duties of the Khalifas were to safeguard and spread Islam.