Answer:
The magnitude of the average induced emf in the loop is 0.1 volts.
Explanation:
let Ф be the flux in the loop, B be the magnetic field and A be the area of the loop.
the induced emf in the loop is given by:
ε = - dФ/dt
 =  - d(B×A)/dt
 = - A×d(B)/dt
 = - π×r^2×d(B)/dt
 = -  π×(0.40)^2×(0.20 - (-0.30))/(2.5 - 0)
 = 0.1 volt
Therefore, the magnitude of the average induced emf in the loop is 0.1 volts.