HELPPP WILL MARK BRAINIEST 18. An incident light beam strikes the edge of its medium at an angle of 42°. The beam refracts at an angle of
90?. Now you know that
a. The critical angle of the medium is 42?.
b. If you decrease the incident angle, the refracted beam will exit the medium.
c. If you increase the incident angle, the refracted beam will not exit the medium
d all of the above

Consider each of the electric- and magnetic-field orientations given next. in each case, what is the direction of propagation of the wave? a)\vec ein the +xdirection,\vec bin the +ydirection. choose+ x direction- x direction+ y direction- y direction+ z direction- z direction b)\vec ein the -y direction,\vec bin the +x choose+ x direction- x direction+ y direction- y direction+ z direction- z direction c)\vec ein the +z direction,\vec bin the -x direction. choose+ x direction- x direction+ y direction- y direction+ z direction- z direction d)\vec ein the +y direction,\vec bin the -z direction. choose+ x direction- x direction+ y direction- y direction+ z direction- z direction