Question

Light inside the thin glass tube of a laproscopic surgical device strikes the edge of the glass tube and is entirely reflected back into the tube, with none of the light exiting to the surrounding medium. Which of the following must be true?

A. θincident = 90º
B. θincident = 0º
C. θincident ≥ θcritical
D. θrefracted = θincident

Answer 1

For total internal reflection in a laparoscopic surgical device, θincident must be greater than or equal to θcritical. This condition enables the entire light to be reflected within the glass tube, a principle applied in fiber optics and endoscopes.

Step-by-step explanation:

In the context of a laparoscopic surgical device involving light transmission through a thin glass tube, the total internal reflection phenomenon is described. For total internal reflection to occur, the condition that must be true is θincident ≥ θcritical. This means the angle of incidence must be greater or equal to the critical angle, where the critical angle is defined as the incident angle that results in an angle of refraction of 90°. When the incident angle exceeds the critical angle, the light ray cannot pass into the less dense medium and is instead reflected entirely within the denser medium, such as the glass of the laparoscopic device. No light escapes to the surrounding medium, which is consistent with total internal reflection essential for devices like endoscopes and fiber optics.