What determine how easily magma flows?

In what direction does the medium move relative to the direction of the wave? explain.

Avery long solenoid of inner radius 2.75 cm creates an oscillating magnetic field of the form = for this solenoid, =0.00425 t and =319 rad/s. (a)what is the maximum value of the induced electric field at a perpendicular distance 1.45 cm from the axis of the solenoid? (b) what is the maximum value of the inducted electric field at a point 5.85 cm perpendicular from the axis of the solenoid?

The frequency of the fundamental of the guitar string is 320 hz. at what speed v do waves move along that string?