Consider a hydrogen atom with the electron in the 2p state. the magnetic field at the nucleus produced by the orbiting electron has a value of 12.5 t.
the proton can have its magnetic moment aligned in ei- ther of two directions perpendicular to the plane of the electrons orbit.
because of the interaction of the protons magnetic moment with the electrons mag- netic field, there will be a difference in energy be- tween the states with the two different orientations of the protons magnetic moment.

find that energy dif- ference in electron volts.

Ababy stroller is a rest on top of a hill which is 10 m high. the stroller and baby have a mass of 20 kg. what is the potential energy of the baby and stroller?

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?

Who was the first scientist to measure speed as distance over time?