Phase contrast microscopy

[@tanmoydas2410]

Please sir tell me the textbook name from which you have taken these images of microscopic principles.

[@thinkscope1091]

@@tanmoydas2410 there are sites like www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=www.microscopyu.com/&ved=2ahUKEwiAu7CAwZGHAxWUTGwGHeEkCtwQFnoECAYQAQ&usg=AOvVaw1UnaqXgF4sAqFD7zm1KICr