If a transformer rating 240vac 50hz being supplied by a source 240vac 60hz,will it get hotter than by 240vac 50hz source?

 

Not noticeably so, no. Losses from the slight increase in frequency will be negligible.

 

If a transformer rating 240vac 50hz being supplied by a source 240vac 60hz,will it get hotter than by 240vac 50hz source?

You will notice a small decrease on the secondary voltage of the transformer but it wont get hotter.

if you do it the other way round, a 60Hz transformer plugged to 50Hz, you will notice a small increase on the secondary's voltage. In this condition, when you reach its rated current you will probably burn it out.