The image position shifts toward which part of the prism: apex or base?

The image position shifts toward which part of the prism: apex or base?

• A. Apex
• B. Base
• C. Centered
• D. No shift

Answer: (A)

The image appears to shift toward the apex. This happens because light is refracted at both faces of the prism. The first refraction bends the ray into the glass, and the second refraction bends it again as it exits. The combined effect is that, when you trace the emergent ray backward into space, it intersects the original line of sight toward the apex side of the prism. For most viewing setups with a simple thin prism, this angular deviation causes the apparent position of a distant object to move toward the apex rather than toward the base.

The image appears to shift toward the apex. This happens because light is refracted at both faces of the prism. The first refraction bends the ray into the glass, and the second refraction bends it again as it exits. The combined effect is that, when you trace the emergent ray backward into space, it intersects the original line of sight toward the apex side of the prism. For most viewing setups with a simple thin prism, this angular deviation causes the apparent position of a distant object to move toward the apex rather than toward the base.