Awhistle you use to call your hunting dog has a frequency of 21 khz, but your dog is ignoring it. you suspect the whistle may not be working, but you can't hear sounds above 20 khz. to test it, you ask a friend to blow the whistle and hop on his moped. in which direction should he ride (toward or away from you) to know if the whistle is working? explain in words or with a diagram

Cells in the nervous system have a potential difference of 70 mv across the cell membrane separating the interior of the cell from the extracellular fluid. this potential difference is maintained by ion pumps that move charged ions across the membrane. is this an emf? select the correct answer and explanation. 1)no. the ion pumps cannot separate charges; thus, they cannot create a potential difference. 2)yes. the ion pumps cannot separate charges, but they still can create a potential difference. 3)yes. the ion pumps can actively separate charge; thus, they can create a potential difference. 4)no. the ion pumps can separate charges, but they cannot create a potential difference.