Question 23.CA.5: Looking through the glass Figure 23.22 shows a setup in whic...
Looking through the glass
Figure 23.22 shows a setup in which two pairs of pins are separated by a block of glass. You observe the pins so that the ray reaching your eye passes through all the pins (Figure 23.22a). Which of the choices in Figure 23.22b represents the apparent position of the pins on the far side of the glass block?
The actual position of the pins below the glass is B. But the eyes can see only the direction of the ray emerging from the top surface of the glass. Nothing about that light ray tells you that it refracted twice as it crossed the two air–glass interfaces. Thus, the apparent position of the pins is A. Notice that the light refracts through the same angle as it crosses from air into glass and then from glass into air. This illustrates the point made in Figure 23.19.
