$$t = \frac{d}{v}$$
Where:
* \(t\) is the time taken
* \(d\) is the thickness of the glass
* \(v\) is the velocity of light in the glass
The speed of light in the glass is given by:
$$v = \frac{c}{n}$$
Where:
* \(c\) is the speed of light in vacuum (approximately \(2.998 \times 10^8\) m/s)
* \(n\) is the refractive index of the glass
For most types of glass, the refractive index is around \(1.5\). Substituting this value into the formula, we get:
$$v = \frac{2.998 \times 10^8}{1.5} = 1.999 \times 10^8\) m/s
Now, we can calculate the time taken for light to pass through the 8.7 cm thick glass:
$$t = \frac{8.7 \times 10^{-2}}{1.999 \times 10^8} = 4.35 \times 10^{-10}\) s
Therefore, it takes approximately \(4.35 \times 10^{-10}\) seconds for light incident perpendicular to the glass to pass through this 8.7 cm thick sandwich.
