The material liyf4 is a laser host that crystallizes in the i41/a group. the y site can be substituted with a range of rare-earth ions and sits on the 4b wycoff site. for a rare earth ion with the transition of 4h5/2 to 4g5/2, three peaks are observed at 562, 557 and 553 nm. what are these peaks in cm-1? the first two peaks are strong but the peak at 553 nm is very weak. perform a spin orbit coupling and determine the stark levels and explain these observations. the authors say for transitions of 4h5/2 to a 4f9/2 state there is a strong polarization effect in polarized light. can you justify this from your stark level analysis? what would you expect to see in polarized light? for this problem just use the same approach as you did in 2 above.

American eels (anguilla rostrata) are freshwater fish with long, slender bodies that we can treat as uniform cylinders 1.0 m long and 10 cm in diameter. an eel compensates for its small jaw and teeth by holding onto prey with its mouth and then rapidly spinning its body around its long axis to tear off a piece of flesh. eels have been recorded to spin at up to 14 revolutions per second when feeding in this way. although this feeding method is costly in terms of energy, it allows the eel to feed on larger prey than it otherwise could. 1.a field researcher uses the slow-motion feature on her phones camera to shoot a video of an eel spinning at its maximum rate. the camera records at 120 frames per second. through what angle does the eel rotate from one frame to the next? 2. the eel is observed to spin at 14 spins per second clockwise, and 10 seconds later it is observed to spin at 8 spins per second counterclockwise. what is the magnitude of the eels average angular acceleration during this time? 3. the eel has a certain amount of rotational kinetic energy when spinning at 14 spins per second. if it swam in a straight line instead, about how fast would the eel have to swim to have the same amount of kinetic energy as when it is spinning? 4.a new species of eel is found to have the same mass but one-quarter the length and twice the diameter of the american eel. how does its moment of inertia for spinning around its long axis compare to that of the american eel?

Erosion of the beach is normally a slow process. however, in certain situations, large chunks of shore may wash out to sea. what could cause this to happen?

Blank liquids and gases exert a buoyant force on objects placed in them