flowing water

Consider a body of flowing water, such as a river. We can describe the flow of river water mathematically by a vector field that describes the water velocity v at every point in the river at an instant of time. Now imagine a small, flat surface submerged in the river. (If you want to visualize something specific, imagine a square grate or a picture frame or something analogous that clearly defines an area but that water can flow through easily.) Assume that the surface is small enough that v is roughly constant over its surface, and that we describe this surface by the tile vector dA. (a) First, imagine that the surface is perpendicular to the water flow in its vicinity, so that the flux o... click for more

Lenz's Rule

Is it necessary for a current to actually flow, or only that you can imagine one flowing if a conductor were present? Describe using Lenz's rule

Magnetic Field

A 1140nF capacitor with circular parallel plates 1.12cm in diameter is accumulating charge at the rate of 20.7mC/s at some instant in time. What will be the induced magnetic field strength 10.8cm radially outward from the center of the plates? What will be the value of the field strength after the capacitor is fully charged?

Determining e/m

I am trying to derive the following from the three equations listed below and need help setting it up 1 √e/m √e/m ---- = ------- Bi + --------- Be r √2V √2V (1)B= Bi - Be( B the net field ) (2)1/2 mv^2 = eV or e/m = v2/2V (e is the charge, m is the mass, V is the potential difference, and v is the final velocity) (3) mv^2/r = evB or e/m = v/Br Thanks for your time/help!

Magnetic Field

In a region of space, the magnetic field increases at a constant rate. This changing magnetic field induces an electric field that (a) increases in time (b) is conservative (c) is in the direction of the magnetic field (d) has a constant magnitude. And why explain? Induced electric field E in Equation 31.9 (see attachment) is a non-conservative field that is generated by a changing magnetic field. Explain what is a non-conservative field.