In user interface bugs we are giving low severity
ex: 1)Improper right alignments(low priority)
    2)spelling mistakes (high priority)
In calculation bug we are giving high severity
ex: 1)final output is wrong(low priority)
    2)dependent outputs are wrong(high priority)

For lowseverity and high priority
If a Login button labeled as CANCEL.

If the application we testing affects the another 
application mean will cme in high priority n high severity..
if its not affect another application then it will cme in 
low priority n low severity

high priority: for  ex  the company name is cmc instead of 
cmc if it is bmc  it is high priority as well as low 
seviority . 

high severity; suppose input range is 0-50
if 15th character doesnt accept it is high severity
if 50th  character doesnot accept it is low priority.
  

if it wrong please correct me

Eg: If companies name is wrong ( spelling mistake ) in all
front end screens, then the seviority is low and priority is
high. Am I Correct. This wont interrupt the program to break
so seviority is low, but comapanie's name should be proper.
so priority is high.