If a light ray is travelling from medium of refractive index '... | General Science MCQ

General SciencePrevious Year Paper 2024

If a light ray is travelling from medium of refractive index ' $n_1$ ' to the medium of refractive index ' $n_2$ ' such that angle of incidence is ' $i$ ' and angle of refraction ' $r$ ' (assuming $0 < i < 90°$ ), then $\frac{n_1}{n_2}$ is equal to ________.

$\frac{\sin i}{\sin r}$

$\frac{\sin r}{\sin i}$

$\frac{\cos i}{\cos r}$

$\frac{\cos r}{\cos i}$

Correct Answer

🔬 SC • Science Concept & PrincipleGeneral SciencePrevious Year Paper 2024

Option C

$\frac{\cos i}{\cos r}$

Quick Summary:

According to Snell's Law of refraction, when a light ray travels from a medium of refractive index $n_1$ into a medium of refractive index $n_2$ , the ratio of the sine of the angle of incidence ( $i$ ) to the sine of the angle of refraction ( $r$ ) is equal to the relative refractive index of the second medium with respect to the first medium ( $\frac{n_2}{n_1}$ ). Conversely, the ratio $\frac{n_1}{n_2}$ is given by $\frac{\sin r}{\sin i}$ .

🎯

Crack Previous Year Paper 2024 with Examoogle SuperTeachers

Get Free Demo Classes & Live Mocks →

🔬SCScience SolutionConcept & Principle

💡 Explanation

💡 Everyday Analogy (Real-World Intuition)

Think of light slowing down and bending when entering water from air; the bending angle depends inversely on how dense the medium is compared to where it came from.

🧠 Memory Mnemonic / Shortcut Aid

Remember 'Sin I over Sin R is n21', so 'Sin R over Sin I is n12'.

🔢 Key Formulas

$n_1 \sin i = n_2 \sin r$ — Snell's Law equation

$\frac{n_1}{n_2} = \frac{\sin r}{\sin i}$ — Ratio of refractive indices

⚙️ Working Principle

Snell's Law states that $n_1 \sin i = n_2 \sin r$ . Rearranging this fundamental optical equation to find the ratio $\frac{n_1}{n_2}$ , we get $\frac{n_1}{n_2} = \frac{\sin r}{\sin i}$ .

📌 Key Points

▸
Snell's law governs the refraction of light at the boundary between two transparent media.
▸
The angle of incidence ( $i$ ) and angle of refraction ( $r$ ) are measured with respect to the normal line.
▸
When a ray goes from a rarer medium ( $n_1$ ) to a denser medium ( $n_2$ ), $n_2 > n_1$ , so $\sin r < \sin i$ .

✅ Advantages

▸
Allows precise calculation of light bending and lens design.

🛠️ Applications / Uses

▸
Optical fiber communication
▸
Lenses, microscopes, and telescopes

📄 Additional Information

▸
Option C is correct because cross-multiplying Snell's law ( $n_1 \sin i = n_2 \sin r$ ) directly yields $\frac{n_1}{n_2} = \frac{\sin r}{\sin i}$ .

📊 Diagram / Illustration

✅

C is correct — according to Snell's Law ( $n_1 \sin i = n_2 \sin r$ ), the ratio $\frac{n_1}{n_2}$ is equal to $\frac{\sin r}{\sin i}$ .

Core Concepts Used

Click any tag to open in AI Tutor

Snell's Law Refractive Index Angle of Incidence and Refraction

💡 EXAM TIP

Always ensure the numerator and denominator indices correspond directly to their respective sine angles when applying Snell's Law.

Was this solution helpful?

⚡ Practice on Android App · 4.8 ★

Solve 10,000+ More Questions with AI Tutor

Get instant step-by-step AI explanations, full shift Previous Year Papers (SSC GD, RRB, SSC JE), and regional rank analysis on the official Examoogle App.

Free Download • 100K+ Aspirants

Discussion (0)

Loading discussion...

Prev Next

Correct Answer

Solve 10,000+ More Questions with AI Tutor

Related Questions

Discussion (0)

Correct Answer

Solve 10,000+ More Questions with AI Tutor

Related Questions

Discussion (0)