You will use your ultrasonic reference data sheet and yourut trigonometry chart for the following practice problems. calculate the 1st critical anglesnell's lawapproximately 27-28 degreesmaterial one is plexiglas. material two is aluminum. we also know that therefracted angle is 90°.approximately 25-26 degreesapproximately 26-27 degreesapproximately 24-25 degreeswhat is the first critical angle? otype here to search^6/4/2 material one is plexiglas. materials two is aluminum. we also know that the refracted angle is 90°. what is the first critical angle