The lens, together with the cornea, can amplify a laser beam by up to how much?

The lens, together with the cornea, can amplify a laser beam by up to how much?

• A. 100,000x
• B. 2x
• C. 10,000x
• D. 1,000x

Answer: (A)

The main idea is how strongly the eye’s optics can concentrate light. The cornea and lens act like a powerful focusing lens, taking light that would otherwise spread out and forming a tiny, bright spot on the retina. Because the total energy stays about the same but is squeezed into a much smaller area, the irradiance (the power per unit area) goes up dramatically. In practical terms, this focusing can increase the beam’s effective energy density by up to about 100,000 times at the retina, which is why lasers can cause retinal damage even if the beam’s power isn’t huge. The other options describe smaller magnifications, which aren’t the typical amplification associated with the eye’s focusing when considering safety.

The main idea is how strongly the eye’s optics can concentrate light. The cornea and lens act like a powerful focusing lens, taking light that would otherwise spread out and forming a tiny, bright spot on the retina. Because the total energy stays about the same but is squeezed into a much smaller area, the irradiance (the power per unit area) goes up dramatically. In practical terms, this focusing can increase the beam’s effective energy density by up to about 100,000 times at the retina, which is why lasers can cause retinal damage even if the beam’s power isn’t huge. The other options describe smaller magnifications, which aren’t the typical amplification associated with the eye’s focusing when considering safety.