Light enters in a glass slab of refractive index 3/2 and covers a distance 20 cm. The optical path of it is

Options

A. 40 cm
B. 30 cm
C. 40/3 cm
D. 60 cm

Answer

To find the optical path length of light traveling through a glass slab, we can use the formula for optical path:

\[ \text{Optical Path} = n \times d \]

where:
- \( n \) is the refractive index of the medium,
- \( d \) is the distance traveled in the medium.

### Step-by-Step Solution:

1. **Identify the Refractive Index**:
The refractive index of the glass slab is given as \( n = \frac{3}{2} \).

2. **Identify the Distance Traveled**:
The distance covered by the light in the glass slab is given as \( d = 20 \, \text{cm} \).

3. **Calculate the Optical Path**:
Substitute the values into the optical path formula:
\[ \text{Optical Path} = n \times d = \left(\frac{3}{2}\right) \times 20 \, \text{cm} \]

4. **Perform the Calculation**:
\[ \text{Optical Path} = \frac{3}{2} \times 20 = \frac{60}{2} = 30 \, \text{cm} \]

5. **Conclusion**:
The optical path length of the light traveling through the glass slab is \( 30 \, \text{cm} \).

### Final Answer:
The optical path of the light is \( 30 \, \text{cm} \).

---