1. If a submarine's sonar can measure echo times with a precision of 0.0100 s. a. What is the smallest difference in distances it can detect? (Assume that the submarine is in the ocean, not in
freshwater.) [5]
b. Discuss the limits this time resolution imposes on the ability of the sonar system to detect the size and shape
of the object creating the echo. [2]

Modern physics a photon emitted from an excited hydrogen atom has an energy of 3.02 electron volts. which electron energy-level transition would produce this photon? a. n=1 to n=6 b. n=2 to n=6 c. n=6 to n=1 d. n=6 to n=2 i chose b but the correct answer is d can someone tell me why? and what's the difference?

What is the measure of a change in an objects velocity?

Arigid tank is divided into two equal parts by a partition. one part of the tank contains 3 kg of compressed liquid water at 400 kpa and 60°c while the other part is evacuated. the partition is now removed, and the water expands to fill the entire tank. determine the entropy change of water during this process, if the final pressure in the tank is 40 kpa. use steam tables.