revenue or capital loss

hello sir,

Q1. if a machine which has become obosolete is sold at 6 year while its estimated useful life is 8 year. why it is treated as revenue loss???

q2.  if a machine which purchased yday and was sold today at a price less than its purchase price.??? will it be revenue or capital loss ???

q3. If a piece of land belonging to the factory is sold at profit. will it be treated as capital profit or revenue profit.

please state the reason for the above mentioned question