For two complex numbers p and q, if Arg(p)-Arg(q)=π/2 as well as |pq|=1, what is the value of p̅q ?

Correct Answer: -i
p̅q=|p|e-iarg p×|q|eiarg q = e-i(arg p-arg q) (since |pq|=1) = e-iπ/2=-i.