Consider an infinitely long solenoid with N turns per unit length, radius R and carrying a current I(t) = a cos wt, where a is a constant and w is the angular frequency. The magnitude of electric field at the surface of the solenoid is (A)H,NRwa sin wt (B) HowNR cos wt (C) H,NRWA sin wt (D) HOWNR cos wt

Figure (a) shows a wire that forms a rectangle (W = 19.0 cm, H = 29.0 cm) and has a resistance of 4.50 mQ. Its interior is split into three equal areas, with magnetic fields B and B B 2' The fields are uniform within each region and directly out of or into the page 1, 3. as indicated. Figure (b) gives the change in the z components B, of the three fields with time t; the vertical axis scale is set by Bg = 4.50 µT and Bp = -2.50B5. What are the (a) the magnitude and (b) direction of the current induced in the wire? B5 H B2 t (s) (a) (b) (a) Number i 2.75E-5 Units A (h) COunterclockwise B. (uT)

Consider two thin wires of length w with a uniform current I as shown in figure below. Determine the magnetic flux density B(F) at the point P(w,w,0). Show the direction of the magnetic flux density at the given point. W I Z W P(w,w,0) y

In modern Magnetic Resonance Imaging (MRI), the system is resistance free. The resistance-free Magnetic Resonance Imaging (MRI) is created by submerging the solenoid electromagnet into a cryogenic liquid such as liquid helium (He).eHH The temperature of liquid helium (He) is 4 Kelvin (K), which is -4,520 Fahrenheit (F). What type of magnet creates the resistance-free system?