Q1. A ring whose mean diameter is 16.0 {rm cm} is wound with a closely spaced toroidal winding of 650 turns.
Calculate the magnitude of the magnetic field at the center of the cross section of the windings when the current in the windings is 0.655 {rm A}.

Q2. Water at a gauge pressure of 3.0 atm at street level flows into an office building at the speed of 0.40 m/s by a pipe 5.0 cm in diameter. The pipe tapers down to 2.20 cm in diameter by the top floor, 15 m above, where the faucet has been left open. Estimate the flow velocity and the gauge pressure in such a pipe on the top floor. Imagine no branch pipes and ignore viscosity.