QUESTION: answer this: critical angle of an interface between a dense medium and air??

ANS: angle of incidence

QUESTION: answer this: when did the new tax cuts go into effect??

ANS: January 1, 2018

QUESTION: answer this: when was the oldest of the telescopes built??

ANS: 1608

QUESTION: answer this: who played oscar in darling buds of may??

ANS:
Ross Marriott