A long solenoid has 231 turns in a length of 13 cm, radius of 1.8 cm, and I= 1.3 A. A 2nd coil of 4 turns w same radius wraps around 1st one. What is change in magnetic flux when current increases to 7.7 A in a period of 1.3 s? Find the magnitude of the average induced emf in the coil. Answer in units of micro V.