The diagram shows the layout of an eye hospital's laser alignment test. A low-power beam is reflected from a patient's cornea and detected by a sensor. The ...

The diagram shows the layout of an eye hospital's laser alignment test. A low-power beam is reflected from a patient's cornea and detected by a sensor. The cornea is a transparent curved surface at the front of the eye and provides much of the refraction of incoming light. The surgeon compares the reflected beam with a reference point before fitting a replacement lens after cataract surgery. The laser has a very low energy and does not damage the eye during the brief test.

(a) Name the process that changes the direction of light as it enters the cornea. [1]
(b) Explain why the curved cornea refracts light rays. [2]
(c) Describe one reason why the test beam has low energy. [1]
(d) Give the name of the opaque eye structure removed in cataract surgery. [1]

Fig. 1 shows a periscope viewer used by a technician to inspect a narrow cable duct. The device contains two plane mirrors and a small convex lens at the eyepiece. Light from an object at the far end of the duct is reflected down the tube and then passes through the lens. The technician adjusts the position of the eye until the image looks sharp. The mirrors alter the direction of light, while the lens allows the technician to inspect a small feature on the cable cap.

(a) Describe the change in direction of light at each plane mirror. [1]
(b) Name the type of lens at the eyepiece. [1]
(c) Explain why the technician uses this lens to inspect a small cable feature. [2]
(d) Give one safety advantage of using the periscope. [1]