In the explanation of laws of refreaction by Newton.s corpuscular theory, identify the true statement

Options

A. he assumed that light travels faster in a denser medium than in a rarer medium
B. he assumed hypothetical medium called ether, near a refracting surface
C. density of ether near the refracting surface is variable within certain range
D. light corpuscles within this range of variable density experiences no force

Answer

To solve the question regarding the true statement in the explanation of the laws of refraction by Newton's corpuscular theory, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Newton's Corpuscular Theory**:
- Newton proposed that light is made up of particles (corpuscles) that travel in straight lines. He used this theory to explain various optical phenomena, including refraction.

2. **Laws of Refraction**:
- The laws of refraction, also known as Snell's Law, describe how light bends when it passes from one medium to another. The bending of light depends on the speed of light in the two media.

3. **Newton's Assumption**:
- According to Newton's corpuscular theory, he assumed that the velocity of light is greater in a denser medium than in a rarer medium. This means that he believed light would travel faster in materials like glass compared to air.

4. **Contradiction with Modern Understanding**:
- However, modern physics tells us that light actually travels faster in rarer mediums (like air) compared to denser mediums (like glass or water). This is a fundamental aspect of wave optics and is contrary to Newton's original assumption.

5. **Identifying the True Statement**:
- Given the context of the question, the true statement regarding Newton's explanation of refraction is that he incorrectly assumed the speed of light is faster in denser media rather than in rarer media.

### Conclusion:
The correct answer to the question is that Newton assumed the velocity of light is faster in denser mediums, which is not true according to modern understanding.