The magnetic field produced by a current in a long straight wire varies with respect to the radial distance r from the wire as Group of answer choices 1/r2. 1/r3. 1/r. r2. r.

An insulated thermos contains 148 g of water at 72.7 ˚c. you put in a 11.7 g ice cube at 0.00 ˚c to form a system of ice + original water. the specific heat of liquid water is 4190 j/kg•k; and the heat of fusion of water is 333 kj/kg. what is the net entropy change of the system from then until the system reaches the final (equilibrium) temperature?