Awire loop of radius 0.40 m lies so that an external magnetic field of magnitude 0.30 t is perpendicular to the loop. the field reverses its direction, and its magnitude changes to 0.20 t in 2.5 s. find the magnitude of the average induced emf in the loop during this time.

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.

a and b sometimes have a positive value

multiply 2kg by latent heat of vap