Answers: 3
Physics, 22.06.2019 07:10
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?
Answers: 2
Physics, 22.06.2019 14:10
Match these items. 1. coulombs __force 2. ohms __emf 3. centimeters __resistance 4. newtons __charge 5. volts __length
Answers: 1
Physics, 22.06.2019 15:20
Acarpenter builds an exterior house wall with a layer of wood 2.9 cm thick on the outside and a layer of styrofoam insulation 2.3 cm thick on the inside wall surface. the wood has k=0.080w/(m⋅k), and the styrofoam has k= 0.010 w/(m⋅k). the interior surface temperature is 19.0 ∘c , and the exterior surface temperature is -15.0 ∘c . a.)what is the temperature at the plane where the wood meets the styrofoam? celsius b.)what is the rate of heat flow per square meter through this wall? /m^2
Answers: 2
Physics, 22.06.2019 17:00
If a negatively charged particle is placed at rest in an electric potential field that increases in the positive x-direction, what will the particle do? a. accelerate in the positive x-direction b. remain at rest c. accelerate in the negative x-direction
Answers: 3
A squirrel jumps down from a tall tree. Assuming the squirrel is in free fall,
how far will it have...
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