AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
$$n_{\text{liquid}} = \frac{\text{Speed of light in air}}{\text{Speed of light in liquid}} = \frac{3 \times 10^8}{2 \times 10^8} = 1.5$$
The refractive index of the liquid with respect to air is 1.5.
Source: Chapter 9, Section 9.3.2 — The Refractive Index
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Use formula $n = \frac{c}{v}$ (Eq. 9.7). Examiners expect the formula, substitution, and final value. No unit for refractive index (it is dimensionless). One mark: write formula + answer in one step.