When the flashlight is in the air and the refracted ray enters the water, how does the angle of refraction compare with the angle of incidence?

The refracted angle will be less than the angle of incidence and the speed of light is slower in the new medium (which is water) and is closer to the normal.

Try remembering this by using FST SFA (Fast Sofa)

                                             Fast -> Slow = Towards the normal

                                             Slow -> Fast = Away from normal

i think it because equal matrices have equal dimensions, only square matrices can be symmetric. for all indices and . every square diagonal matrix is symmetric, since all off-diagonal elements are zero. in linear algebra, a real symmetric matrix represents a self-adjoint operator over a real inner product space.

see earlier answer