3. The magnetic field between the coils is given by: B = 520µ0 I (1/x1 + 1/x2) where xi =Ri [4 + (d/Ri) 2 ] 3/2 with Ri their radius and d their separation. a) From the above result the magnetic field between the coils can be written as B = kI for some constant k that depends on the geometry of the coils. Using your values for R1, R2, and d, calculate k. Attempt to estimate the uncertainty on k. k = b) If you were able to determine a non-zero coil current to offset the earth’s magnetic field in part 2, use the above result to determine the component of the room magnetic field BE along the coil axis. How does your estimate for BE compare with the horizontal Earth field component in Santa Monica BE ≈ 0.245 gauss?