Answer:
The speed of light in the medium is
![(2c)/(3)](https://img.qammunity.org/2020/formulas/physics/college/1z04qe1wvx88qxtxcmorca8n2r4j28k3ho.png)
(c) correct option.
Step-by-step explanation:
Given that,
Speed of light in vacuum = c
Refraction index = 1.5
We need to calculate the value of speed of light in the medium
The refractive index is equal to the speed of light in vacuum divide by the speed of light in medium.
Using formula of refractive index
![\mu = (c)/(v)](https://img.qammunity.org/2020/formulas/physics/college/2qwqyc290le2lx46z3doy13m09o7agoagc.png)
![v=(c)/(\mu)](https://img.qammunity.org/2020/formulas/physics/college/gpvo6dh2xdp0kdhwklth5rdcbz4lrbgxn9.png)
Where, c = speed of light in vacuum
v = speed of light in medium
Put the value into the formula
![v=(c)/(1.5)](https://img.qammunity.org/2020/formulas/physics/college/qwhk3l3oap1hjs81zydrqcf75xl7858tjf.png)
![v=(2c)/(3)](https://img.qammunity.org/2020/formulas/physics/college/i0xkmuxzfil21glw7j0umfwzvzzacj163c.png)
Hence, The speed of light in the medium is
![(2c)/(3)](https://img.qammunity.org/2020/formulas/physics/college/1z04qe1wvx88qxtxcmorca8n2r4j28k3ho.png)