''The apple is sweet'' is a wrong answer... because the hindi sentence has the word ''hotha''...
No. The copula is used in the habitual tense to tell facts. Apples are sweet. The apple is sweet would be, 'सेब मीठा है'
"Hotha" describes about the 'habitual' or 'usual' condition... if we say "Seb meeta hotha he" it'd mean that "all apples are (habitually/usually) sweet"...
Sorry I don't have a hindi keyboard. "seb meetha hai" would translate as "the apple is sweet", where you are talking about a 'the' particular apple. "Seb meetha hota hai" translates as "Apples are sweet" where you are describing the general taste of Apple fruit.
The apple is sweet. It doesn't necessarily mean that we are talking about ALL apples, All the time. It can mean that the apple (you gave me) is sweet. Or, The apple (that I am eating now) is sweet. I don't have to say THIS apple is sweet. I just say, 'The apple is sweet.'
Hota makes it a general statement - all apples are sweet rather than just this specific apple is sweet.