In a certain vacuum tube, electrons evaporate from a hot cathode at a slow, steady rate and accelerate from rest through a potential difference of 47.0 v. then they travel 28.5 cm as they pass through an array of slits and fall on a screen to produce an interference pattern. if the beam current is below a certain value, only one electron at a time will be in flight in the tube. in this situation, the interference pattern still appears, showing that each individual electron can interfere with itself. what is the maximum value for the beam current that will result in only one electron at a time in flight in the tube?

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?

Atomic nuclei of almost all elements consist of

In a set amount of time, a battery supplies 25j of energy to an electric circuit that includes two different loads. one of the loads produces 10 j of heat energy during this time interval. how much heat energy is produced by the second load in this time? explain your answer