light ray is refracted

A LIGHT RAY IS REFRACTED IN A CERTAIN MEDIUM. WHICH OF THE FOLLOWING IS NOT TRUE?
sinar cahaya telah dibiaskan dalam suatu bahantara. Yang manakah di antara berikut tudak benar?

A ITS DIRECTION IS CHANGED
    arahnya berubah
B ITS SPEED IS CHANGED
    kelajuannya berubah
C ITS FREQUENCY IS CHANGED
    frekuensinya berubah



ANSWERS : C