Hey Sonali, nice topic.......
One thing, to teach or learn history; films, documentary, serials are the best options rather than books. (Books are best for those who go research in History).
Ok I think ,whether to make a film or serial, depends on the story u have choosed. How much relevant data is available? Proofs available? How big the story of particular person or era is?
Like say for example Mahabharat or Ramayan: We have lots and lots of material for it. Also each character has a long story. Its not possible to make a film on topic Mahabharat, bcoz u cannot show every detail available. So going for a serial is the best option. Also Shivaji's story is so vast, I hope someone starts a serial on him instead of film.
For stories like Bhagat Singh: Story is not that big, so serial will hardly have 100 episodes. So film is the best choice here. Also Mughale Aazam, Akbar.
For Prithvi Raj: Serial is the best option becoz there r many small stories which cannot be covered in 3 hrs film and it won't give that effect which serial ll give. Also Sequel option is fine. Like harry potter series (PRC and Khajana Khoj, PRC and yatra, PRC and Swayamvar). And In Sagars DKVY-PRC they added masala for only one reason- to extent the role of lead actors. Otherwise they were going acc to history.