What is difference between RADIO drama and Television drama?

Radio drama's best action is in the relationship of characters. Love, hate, passion, all that stuff goes really well in audio only as expressed in voices, dialogue and narration if needed. Even the most passionate scenes expressed in groans and sighs are really Excellent because they leave a lot to the imagination and increase listener involvement. Just don't try to do a Fencing duel in a radio show. Any play-by-play would have to be in French to describe it and the attendant grunts and groans of the participants don't clue in the listener very well.

Conversely, television and visual storytelling thrives on fights, chases, all kinds of tussles. The best TV and film stimulates the eye with intriguing angles and colors, characters whose faces the camera loves and fast paced, breath-taking action. But perversely, watcher involvement can be shallow as the images become eye candy and easily forgotten. Even more perversely music and sound effects, the audio presence of visual storytelling is crucial to clueing the viewer into the correct emotion. Just watch some TV movies with the sound down to test this well-known effect.

Radio drama presents an audio outline of the story which the listener willingly fills in with their own internal impressions (in all senses.) The best visual drama also uses the imagination to stimulate the viewer. Most film is biased toward the eyesight's fickle preference for fast-moving bright pictures along with supportive audio to move the story along at the cinematographer's and editor's choices, not the viewers.