Answer:
An impairment has occurred because expected net future cash flow (250,000) are less than the carrying amount ($400,000). The loss is measured as the difference between the carrying amount and fair value ($310,000).
Date Description and Explanation Debit Credit
Loss on impairment $90,000
Patents ($400,000 - $310,000) $90,000
(To record the loss on Impairment)