Aconducting bar slides without friction on two parallel horizontal rails that are 50 cm apart and connected by a wire at one end. the resistance of the bar and the rails is constant and equal to 0.10 ω. a uniform magnetic field is perpendicular to the plane of the rails. a 0.080-n force parallel to the rails is required to keep the bar moving at a constant speed of 0.50 m/s. what is the magnitude of the magnetic field?

Asap 1. which surface feature of the moon is characterized by mountainous areas? question options: maria terrae regolith craters 2.which statement describes surface features called maria on the moon? question options: layers of dust and rock deep areas of cooled lava deep, rocky and barren valleys highlands and mountainous areas

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?

When the magnetic domains in a material can be aligned, but eventually drift out of alignment, the material is