Consider an InGaAs APD with x ≈ 0.7 which is biased to operate at M = 10. The unmultiplied dark current is 10 nA and bandwidth is 700MHz. a) What is the APD noise current per square root of bandwidth?
b) What is the APD noise current for a bandwidth of 700MHz?
c) If the responsivity (at M = 1) is 0.8 AW -1 what is the minimum optical power for a SNR of 10?

Assuming weightless pulleys and 100% efficiency, what is the minimum input force required to lift a 120 n weight using a single fixed pulley?

Is it possible to use the energy from two atoms colliding to create a clean burning lasting fuel source with a large amount of force? is it also possible to harness that energy from the two atoms colliding to create a clean energy source that will last for years from just two atoms colliding. is there a possibility to control and store that energy for years but slowly let the energy out enough to power cities cheaper and faster.

What are similarities and differences of reflection, refraction, diffraction and absorption?