induced emf in secondary coil - help ASAP Please 1. The problem statement, all variables and given/known data A very long, straight solenoid with a cross-sectional area of 6.00 cm2 is wound with 40.0 turns of wire per centimeter, and the windings carry a current of 0.250 A. A secondary winding of 2.00 turns encircles the solenoid at its center. When the primary circuit is opened, the magnetic field of the solenoid becomes zero in 5.00×10−2 s . What is the average induced emf in the secondary coil? 2. Relevant equations E = Delta flux / delta time flux = BA cos Theta B = U0*n*I 3. The attempt at a solution I have no idea where to begin. to find the flux I need the Magnetic Field. I do not know the magnetic field value so How can I find flux to in turn find E? Please get me started correctly. I think I have found B on the first coil. B = U0*n*I B = U0*240*0.250A I used 240 as it is 40 turns per cm. B = 7.54*10-5 ??? then if i fund flux of coil 1 = flux = BA fulx = 7.54*10-5 * .0006 m2 = 4.53*10-8 ??? i tried doing the same for the other coil, but I do not have anything to get area of that coil. i used: N1/N2 = I1/I2 for I2 and got I2 = .0125A ????