structure and function of eye

 definition of eye :- The human is an organ that converts light into a set of electrical signals and transmits these these signals to the brain.  

Q. why do eyes of animals shine in the night ?

ans. They have a special type of reflective layer behind the pupil of their eyes known as tapetum lucidum.

cornea :-  the cornea is the outer layer at the front of the eye. transparent structure at the front of the eye. 

• The cornea helps our eye to focus light so we can see clearly.
• The cornea acts as the eye's outer most lens. controls and focuses the entry of light into the eye.
•  The cornea is shaped like a dome and bends light to help the eye focus. It is the eyes primary light focusing structure.
  
  

Anterior chamber :- Anterior chamber is the part of the eye between the cornea and the iris.

The anterior chamber is filled with a watery fluid known as the aqueous humor. anterior chamber is 3mm deep and it contains 0.25ml of the aqueous humor.

Iris :- The colored tissue in eye that contans the pupil in the center. The iris helps control the size of the pupil.

Q.  What is the function of iris in the eye ?

ans.- The iris controls the amount of light that enters the eye.

• The iris lies in front of the crystalline lens and separates the anterior chamber from the posterior chamber.

Q.  Why is iris colored ?

ans.- The color of the iris is based on the amount of pigment, or melanin.

• The more pigment present the darker the eyes.

Pupil :- The pupil is the opening in the center of the iris. Function of the pupil is to allow light to enter the eye so it can be focused on the retina . the pupils appear perfectly round and black in color.

Q . Why is pupil black ? 

ans.- The black color is because light that passes through the pupil is total abserbed by the retina and is not reflected back.  

in low light conditions -  the pupil dilates so more light can reach the retina to improve night vision.

in bright condition - the pupil constricts 

  

Generally normal pupil size in adults ranges from 2 to 4 millimeters in bright light to 4 to 8mm in the dark.

both pupils normally constrict when you focus on a near object.

Rectangular pupil - sheep, Goats , octopuses and toads 

spherical - human 

vertical slite - cats, snakes alligators and crocodiles.

मलिक मुहम्मद जायसी

 जन्म :- 1492  (अनुमानतः )

निधन :- 1548 (अनुमानतः )

निवास स्थान :- जायस (उतर प्रदेश )

पिता :- मालिक शेख ममरेज 

गुरु :- सूफी संत मोहिदी और  सैयद अशरफ 

 वृत्ति :- आरंभ में जायस में रहते हुए  किसानी,  शेष जीवन फकीरी में ,  बचपन में  ही  अनाथ 

व्यक्तित्व  :-   बायीं आँख और बायीं कान नहीं था चेचक के कारण 

कृतियाँ :- पद्मावत , अखरावट , आखिरी कलाम , 

Meaning of Debit and Credit

 The very word 'Debit' is derived from the Latin word 'debitum' which means 'due from that' or 'who owes'. But technically, to debit an account means to write on the left hand side of an account called the debit side. In short, debit refers to the left hand side an account. It increases either assets or the recorded expenditure of the organisation keeping the book. The term Debit is related to the English term 'Debtor'. Debit is written in short form as 'Dr'.

Similarly, the word 'Credit' is derived from the Latin word 'Creditum' or 'Creder' which reveals 'due to that'. But to credit an account means to write on the right hand side of account which is called the 'Credit side'. In short, it is written as Cr. Usually credit side shows sale, income or liability.

Practically, these two terms are the two sides of an account, the left hand side is called the Debit side and the right hand side is called the Credit side.

Thomson's Model of the Atom

 Thomson suggested in 1898  that the atom is a positively charged solid sphere and electrons are embedded in it in sufficient number so as to make the atom electrically neutral. One can compare Thomson's atom to a birthday cake in which cherries are embedded. This model was quite attractive as it could explain why only negatively charged particles are emitted when a metal is heated and never the positively charged particles. 

Modern Classification of accounts or Accounting Equation

 Accounts are divided into five categories for the purpose of recording business transactions : 

1. Assets Accounts 

2. Liabilities Accounts

3. Capital Accounts 

4. Expenses Accounts 

5. Revenue Accounts

1. Assets Accounts :- assets accounts are accounts of assets and properties such as (Stock), Goodwill, Prepaid Expenses A/c .... etc.

2. Liabilities Accounts :- Liabilities accounts are the accounts of lenders, bank loan , bank overdraft , outstanding expenses, .... etc.

3. Capital Accounts :- Capital accounts refer to the accounts of the proprietor/ partner who have invested in the business, eg, Capital account of owner, Drawings accounts, ...etc.

4. Expenses Accounts :- Expenses accounts is an accounts opened in the nominal ledger for each expenditure in which the costs or expenses are recorded before being totalled and transferred to trading and profit and loss Account at the end of an accounting period.

5. Revenue Accounts :- Revenue Accounts are accounts of incomes and gains. eg.- sales A/c, interest received A/c,....etc.