The refractive index of glass is 1.5. The speed of light in glass is

Options

A. `3 xx 10^(8)` m//s
B. `2 xx 10^(8)` m/s
C. `1 xx 10^(8)` m/s
D. `4 xx 10^(8)` m/s

Explanation

To find the speed of light in glass given the refractive index, we can use the relationship between the speed of light in a vacuum (or air) and the speed of light in a medium, which is defined by the refractive index.

### Step-by-Step Solution:

1. **Understand the Refractive Index**:
The refractive index (μ) of a medium is defined as the ratio of the speed of light in vacuum (or air) to the speed of light in the medium. Mathematically, this is expressed as:
\[ \mu = \frac{c}{v} \]
where:
- \( \mu \) = refractive index of the medium (for glass, \( \mu = 1.5 \))
- \( c \) = speed of light in vacuum (approximately \( 3 \times 10^8 \) m/s)
- \( v \) = speed of light in the medium (in this case, glass)

2. **Rearranging the Formula**:
We can rearrange the formula to solve for the speed of light in glass:
\[ v = \frac{c}{\mu} \]

3. **Substituting Known Values**:
Substitute the known values into the equation:
\[ v = \frac{3 \times 10^8 \, \text{m/s}}{1.5} \]

4. **Performing the Calculation**:
Now, calculate the speed of light in glass:
\[ v = 2 \times 10^8 \, \text{m/s} \]

5. **Conclusion**:
Therefore, the speed of light in glass is \( 2 \times 10^8 \, \text{m/s} \).

### Final Answer:
The speed of light in glass is \( 2 \times 10^8 \, \text{m/s} \).