Answer:
15/f s
Explanation:
The refractive index n = 1.5 of the glass is n = λ₁/λ₂ where λ₁ = wavelength of monochromatic light in vacuum = L/10 and λ₂ = wavelength of monochromatic laser in glass.
So, λ₂ = λ₁/n.
We know the speed of light in glass, v = fλ₂ and λ₂ = v/f.
The light covers a distance d = L in time, t = d/v (since v = d/t)
So, the time it takes the pulse of light to travel from one end of the glass to the other is t = d/v = L/fλ₂ = L/fλ₁/n = nL/fλ₁ = nL/fL/10 = 10 × 1.5/f = 15/f s
So, the time it takes the pulse of light to travel from one end of the glass to the other is t = 15/f s