Consider a 60-cm long HeNe laser (633 nm) that operates on two adjacent longitudinal modes of equal amplitude A and identical polarization. The laser illuminates a photodiode with a 1-ns response time. The diode output is monitored on a 1-GHz oscilloscope. Derive an equation for the signal as a function of time. Sketch the oscilloscope trace that you expect and comment.

Idon't know it i just need my points lol

Distance covered = speed x timethe distance traveled going against the stream = distance traveled with the stream.therefore it is the speed and the time that are the variables.as he travels the same distance both ways, speed x time is the same for each way.going upstream his speed is 4 kph; going downstream his speed is 6 kph.therefore we have two simultaneous equations: time upstream x 4 = time downstream x 6time upstream + time downstream = 60 minutestherefore we have the equation: time upstream = 6/10 hour, time downstream therefore = 4/10 hour.distance traveled at 4km/hr in 6/10 hour = 24/10 = 2.4km.check: distance traveled at 6km/hr in 4/10 hour = 24/10 = 2.4km.