The refractive indices of materials [tex]$A$[/tex] and [tex]$B$[/tex] have a ratio of [tex]$\frac{n_A}{n_B} = 1.41$[/tex]. The speed of light in material [tex]$A$[/tex] is [tex]$1.05 \times 10^8 \, \text{m/s}$[/tex]. What is the speed of light in material [tex]$B$[/tex]?

Units: [tex]\text{m/s}[/tex]



Answer :

Certainly! Let's find the speed of light in material [tex]\( B \)[/tex] step-by-step.

### Step-by-Step Solution:

1. Understand the Relationship Between Refractive Index and Speed of Light:
The refractive index ([tex]\( n \)[/tex]) of a material is inversely proportional to the speed of light ([tex]\( v \)[/tex]) in that material. Mathematically, for two materials [tex]\( A \)[/tex] and [tex]\( B \)[/tex]:
[tex]\[ \frac{n_A}{n_B} = \frac{v_B}{v_A} \][/tex]
Given:
[tex]\[ \frac{n_A}{n_B} = 1.41 \][/tex]
and the speed of light in material [tex]\( A \)[/tex] is:
[tex]\[ v_A = 1.05 \times 10^8 \text{ m/s} \][/tex]

2. Express the Speed of Light in Material B Using the Given Ratios:
Rearrange the relationship to solve for [tex]\( v_B \)[/tex]:
[tex]\[ v_B = v_A \times \frac{n_B}{n_A} \][/tex]
Since [tex]\( \frac{n_B}{n_A} = \frac{1}{1.41} \)[/tex], we get:
[tex]\[ v_B = v_A \times \frac{1}{1.41} \][/tex]

3. Substitute the Given Values:
Plug the value of [tex]\( v_A \)[/tex] into the equation:
[tex]\[ v_B = 1.05 \times 10^8 \, \text{m/s} \times \frac{1}{1.41} \][/tex]

4. Calculate the Result:
Perform the division:
[tex]\[ v_B = 1.05 \times 10^8 \, \text{m/s} \div 1.41 \][/tex]
Carrying out the division:
[tex]\[ v_B \approx 74468085.11 \, \text{m/s} \][/tex]

### Conclusion:

The speed of light in material [tex]\( B \)[/tex] is approximately [tex]\( 7.45 \times 10^7 \, \text{m/s} \)[/tex] or [tex]\( 74468085.11 \, \text{m/s} \)[/tex].

Thus, the speed of light in material B is [tex]\( 74468085.11 \, \text{m/s} \)[/tex].