When cleaning up a local beach, students found many different particles that were in the water that affected the shoreline, like litter and gasoline. which of the following describe how these items would need to separated from the water? why? a. both gasoline and litter would need to be chemically separated from the water, because both form new bonds with the water. b. litter would need to be physically separated with water and gasoline would need to be chemically separated from water, because both form a mixture with the water. c. both gasoline and litter would need to be chemically separated from the water, because neither bonds with the water. d. both gasoline and litter would need to be physically separated from the water, because neither bonds with the water. (p. s. do teachers know about this? like fr)

Search coils and credit cards. one practical way to measure magnetic field strength uses a small, closely wound coil called a search coil. the coil is initially held with its plane perpendicular to a magnetic field. the coil is then either quickly rotated a quarter-turn about a diameter or quickly pulled out of the field. (a) derive the equation relating the total charge q that flows through a search coil to the magnetic-field magnitude b. the search coil has n turns, each with area a, and the flux through the coil is decreased from its initial maximum value to zero in a time ∆t. the resistance of the coil is r, and the total charge is q = i∆t, where i is the average current induced by the change in flux. (b) in a credit card reader, the magnetic strip on the back of a credit card is rapidly “swiped” past a coil within the reader. explain, using the same ideas that underlie the operation of a search coil, how the reader can decode the information stored in the pattern of magnetization on the strip. (c) is it necessary that the credit card be “swiped” through the reader at exactly the right speed? why or why not?