Understanding Refractive Index and Light Bending

This question involves calculating the relative refractive index between two media (water and dense flint glass) and determining how a light ray bends when passing from one medium to another.

Calculating Refractive Index from Glass to Water

The refractive index of one medium with respect to another is calculated by dividing the refractive index of the second medium by the refractive index of the first medium.

Let:

• Refractive index of water, $n_{water} = 1.33$
• Refractive index of dense flint glass, $n_{glass} = 1.65$

The light ray travels from dense flint glass (medium 1) to water (medium 2).

The refractive index of water with respect to dense flint glass ($n_{water/glass}$) is calculated using the formula:

$$ n_{water/glass} = \frac{n_{water}}{n_{glass}} $$

Substituting the given values:

$$ n_{water/glass} = \frac{1.33}{1.65} $$

Calculating the value:

$$ n_{water/glass} \approx 0.806 $$

Rounding to two decimal places, the refractive index is 0.81.

Determining Light Bending Direction

When light travels from one medium to another, its path changes direction based on the refractive indices of the media. This phenomenon is governed by Snell's Law.

In this case, the light ray travels from dense flint glass ($n_{glass} = 1.65$) to water ($n_{water} = 1.33$).

We observe that:

• $n_{glass} > n_{water}$ (1.65 > 1.33)

This means the light is moving from a optically denser medium (glass) to an optically rarer medium (water).

Rule: When light travels from an optically denser medium to an optically rarer medium, it bends away from the normal.

Conclusion

Based on the calculations and the rules of light refraction:

• The refractive index of water with respect to dense flint glass is approximately 0.81.
• The light ray bends away from the normal when entering water from dense flint glass.

Therefore, the correct option is the one stating '0.81; away from'.