A ray of light in air meets a rectangular glass block (n = 1.50) of thickness 6.0 cm…

Step 1. The angle of refraction. $\sin r = \dfrac{\sin 60°}{1.50} = \dfrac{0.866}{1.50} = 0.577$, so $r = 35.3°$.

Step 2. The shift. $d = \dfrac{t\sin(i - r)}{\cos r} = \dfrac{6.0\ \text{cm} \times \sin 24.7°}{\cos 35.3°} = \dfrac{6.0\ \text{cm} \times 0.418}{0.816} = 3.07\ \text{cm}$.

Step 3. The path in the glass. The path length is $\dfrac{t}{\cos r} = \dfrac{6.0\ \text{cm}}{0.816} = 7.35\ \text{cm}$.

Step 4. The time. The speed in glass is $v = \dfrac{c}{n} = \dfrac{3.00 \times 10^{8}\ \text{m/s}}{1.50} = 2.00 \times 10^{8}\ \text{m/s}$. The time is $\dfrac{0.0735\ \text{m}}{2.00 \times 10^{8}\ \text{m/s}} = 3.67 \times 10^{-10}\ \text{s} = 0.367\ \text{ns}$.