Alyssa is taking a walk on a nature path near her neighborhood. She carries a compass with her. As she walks along the path, she notices
the needle on the compass is occasionally deflected from its original
position. If she has not changed the direction she is walking, what is
most likely causing the occasional shift in the needle? (1 point)
O Changes in pressure
0 Changes in temperature
O Sources of electrical current
O Changes to Earth's magnetic field

People with normal vision cannot focus their eyes underwater if they aren't wearing a face mask or goggles and there is water in contact with their eyes. in a simplified model of the human eye, the aqueous and vitreous humors and the lens all have a refractive index of 1.40, and all the refraction occurs at the cornea, whose vertex is 2.60 cm from the retina.with the simplified model of the eye, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object? (be careful-the focal length of a lens underwater is not the same as in air! assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. assume that the eyeglasses are 2.05cm in front of the eye.)