100 !

cell phones depend on both mechanical and electromagnetic waves to be useful. which answer below correctly identifies how each wave is used in cell phones?

mechanical waves allow the cell phone to emit a sound when ringing; electromagnetic waves allow a signal to be picked up when making a call.

mechanical waves allow a signal to be picked up when making a call; electromagnetic waves allow the cell phone to emit a sound when ringing

mechanical waves allow the buttons to be pressed to make a call; electromagnetic waves allow a signal to be picked up when making a call

mechanical waves light up the screen; electromagnetic waves create the sound when the phone is ringing

Two nitro no2 groups are chemically bonded to a patch of surface. they can't move to another location on the surface, but they can rotate (see sketch at right). it turns out that the amount of rotational kinetic energy each no2 group can have is required to be a multiple of ε, where =ε×1.010−24 j. in other words, each no2 group could have ε of rotational kinetic energy, or 2ε, or 3ε, and so forth — but it cannot have just any old amount of rotational kinetic energy. suppose the total rotational kinetic energy in this system is initially known to be 32ε. then, some heat is removed from the system, and the total rotational kinetic energy falls to 18ε. calculate the change in entropy. round your answer to 3 significant digits, and be sure it has the correct unit symbol.