In an ideal step-up transformer the primary voltage is vp=170sin(100πt)V and the turns ratio is Ns:Np=10:1. Determine the earliest positive time (in milliseconds, correct to two significant figures) at which the instantaneous secondary voltage first attains +800V.
a) 5.0ms
b) 1.1ms
c) 1.6ms
d) 0.79ms