49. Process of adding impurities to semiconductor is called- 
                
             
         
        
                    
                            
                    ব্যাখ্যা: ব্যাখ্যা: The process of adding controlled inpurities to a semiconductor is known as "doping" The amount of impurity, or dopant, added to as intrinsic (pure) semiconductor varies its level of conductivity.