what is process scheduling in operating system

generally ye multi programming process hoti hai, kuchh process continue run hoti hai. taki cpu ka adhik se adhik use kiya ja sake. time sharing system ka aim yah hota hai ki cpu ko process ke beech itna fast switch kiyajaye ki user every program se unke run hone ke samay interact kar sake ek uni processor system me ek se adhik process ho to unhe cpu k free hone tatha fir se schedule kiye jane ke liye wait karna padta hai jab ek process ko kisi reason se wait karna padta hai to operating system cpu ko us process se return lekar kisi dusari process ko de deta hai arthat jab bhi kisi process ko wait me rakha jata hai uske sthan par kisi dusari process ko cpu timing ko use karne ke liye permission provide karte hai.