Eddy Current Testing

For an ultrasonic beam with normal incidence, the transmission coefficient is given by:

[(Z1 + Z2)^2] / [(Z1 - Z2)^2]

(Z1 + Z2) / (Z1 - Z2)

[4 * Z1 * Z2] / [(Z1 + Z2)^2]

[(Z1 - Z2)^2] / [(Z1 + Z2)^2]

None of the above