semiconductor diode -i-v charactersticcs in forrward and reverse bias???
The answer to the question that you have posted can be found in the NCERT-PART II text book page no 479,480,481 and 482.
Answers to the questions you have asked can be found exactly in the textbook with all the proper explanations needed. Please go through it and if you have any doubt regarding the concepts, we would be glad to help you with it.