adjusting entrise are those entries which are done to 
rectify errors.

I'll make it easy by a simple example
Actual salary paid by the company is Rs10000
But there is an outstanding amount of Rs2000 payable to the 
employee. Expense side of the P&L account should show the 
total amount(salary paid and payable)
Salary A/C
To Salary outstanding

Adjusting entries are prepared at end of the accounting 
year for reflect the correct balance between cash method 
and accural method

The need to pass adjustment entries to close down the 
revenue accounts with the  full utilisation in the 
financial year and to rectify the mistakes if any in the 
passing of entries

adjustment entries are doing to tally balance sheet itmes.

ADJUSTING ENTRIES ARE PREPARED AT THE END OF THE 
ACCOUNTING  PERIOD FOR CORRECT BALANCE REFELECT THE INCOME 
AND EXPENDITUR BETWEEEN THE CASH AND ACCURAL METHODS