A long, straight, current-carrying wire runs across the floor in a lab. At a distance of 0.250.25 meters from the wire, the magnetic field due to the wire is found to be 2.75~ \mu \text{T}2.75 μT and directed into the floor. What is the magnitude of the magnetic field at a distance of 0.750.75 meters from that same wire?

Afisherman notices that his boat is moving up and down periodically without any horizontal motion, owing to waves on the surface of the water. it takes a time of 2.20 s for the boat to travel from its highest point to its lowest, a total distance of 0.670 m . the fisherman sees that the wave crests are spaced a horizontal distance of 5.80 m apart. (a) how much is the wavelength? (b) find the period of the wave. (c) how fast are the waves traveling? (d) what is the amplitude a of each wave?