Light travels through a glass plate of thickness d and having refractive index `mu`. If c is velocity of light in vacuum, the time taken by light to travel this thickness of glass is

Options

A. `(mud)/c`
B. `t/(muc)`
C. `mucd`
D. `(cd)/mu`

Explanation

To find the time taken by light to travel through a glass plate of thickness \( d \) and refractive index \( \mu \), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the relationship between speed, distance, and time**:
The basic formula that relates distance, speed, and time is:
\[ \text{Time} = \frac{\text{Distance}}{\text{Speed}} \]

2. **Identify the speed of light in the medium**:
The speed of light in a vacuum is denoted as \( c \). When light travels through a medium such as glass, its speed decreases and can be expressed as:
\[ V = \frac{c}{\mu} \]
where \( \mu \) is the refractive index of the glass.

3. **Substitute the values into the time formula**:
The distance the light travels through the glass is \( d \). Therefore, substituting the values into the time formula gives us:
\[ t = \frac{d}{V} = \frac{d}{\frac{c}{\mu}} = \frac{d \cdot \mu}{c} \]

4. **Final expression for time**:
Thus, the time taken by light to travel through the glass plate is:
\[ t = \frac{\mu d}{c} \]

### Conclusion:
The correct answer for the time taken by light to travel through the glass plate of thickness \( d \) with refractive index \( \mu \) is:
\[ t = \frac{\mu d}{c} \]