In a scenario where light passes sequentially through three different media (air, water, and glass), which rule helps predict the final direction of the light ray?

1. A

   Principle of Superposition

2. B

   Snell's Law

3. C

   Law of Gravitation

4. D

   Law of Conservation of Energy

Appeared in: RRB Nsg. Superintendent-2026 (Shift -3rd)

Explanation

• Snell's Law, also known as the law of refraction, is the correct principle.
• It mathematically relates the angle of incidence and the angle of refraction to the refractive indices of the two media.
• To find the final path of light through multiple layers (like air, water, and glass), Snell's Law is applied at each boundary crossing in sequence.
• The formula n₁ sin(θ₁) = n₂ sin(θ₂) allows for precise calculation of the light ray's direction in each medium.

Why Other Options Were Wrong

• Option A: This principle describes how wave amplitudes combine during interference or diffraction.
• Option C: This law describes the force of attraction between masses and is unrelated to the path of light.
• Option D: This fundamental law states that energy is conserved, but it does not provide information about the geometric path or direction of a light ray.

Related Visual

• Visual 1: Diagram - A ray diagram showing a light ray passing from a medium with a low refractive index (like air) through two subsequent media with higher refractive indices (like water and glass). The diagram should label the normal, the angle of incidence, and the angle of refraction at each interface, illustrating how the ray bends toward the normal as it enters a denser medium.

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain The concept tested is the refraction of light and the physical law that governs it as background academic context rather than a clinical decision trigger.
• While this is a physics concept, it is the basis for all optics, which is critical in many medical technologies that nurses use or encounter.
• The functioning of eyeglasses, contact lenses, microscopes, endoscopes, and fiber optic instruments used in diagnostics and surgery are all based on the principle of refraction (Snell's Law).
• The human eye itself functions as a complex lens system, refracting light to focus it onto the retina. Understanding refraction is key to understanding vision correction.

How to Approach the Question

• First, identify the core physical phenomenon described in the question. Here, it's about a light ray changing direction as it passes through different materials.
• Recognize this phenomenon as 'refraction'.
• Scan the options to find the physical law that specifically describes refraction.
• Snell's Law is the specific law of refraction. The other options are valid physical principles but apply to different phenomena (wave interference, gravity, energy conservation).
• Eliminate the distractors by recalling what each law describes. The Law of Gravitation is clearly unrelated. The Principle of Superposition deals with wave combination, and Conservation of Energy is too general to predict a specific path.

Concept Tested & Keywords

• Concept Tested: The concept tested is the refraction of light and the physical law that governs it.
• Stem keywords: light, sequentially, three different media, air, water, and glass, final direction
• Lead-in keywords: which rule

Question ID

Qr2LMWQfprnuRud1E-wH45

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