The 20-m-radius laser ablation pit in Figure 20-28 was created by a laser pulse with a duration

The 20-μm-radius laser ablation pit in Figure 20-28 was created by a laser pulse with a duration of 10 ns and an energy of 2.4 mJ. Express the laser power density in units of W/cm2. Recall that 1 W 1 J/s. If the depth of the pit is 1 μm and the density of the material is 4 g/mL, how much mass is removed by one pulse?