You want to estimate the diameter of a very small circular pinhole that you've made in a piece of aluminum foil. to do so, you shine a red laser pointer (λ = 632 nm) at the hole and observe the diffraction pattern on a screen 3.4 m behind the foil. you measure the width of the central maximum to be 12 mm .

A47.2 g block of copper whose temperature is 480 k is placed in an insulating box with a 91.8 g block of lead whose temperature is 200 k. (a) what is the equilibrium temperature of the two-block system? (b) what is the change in the internal energy of the two-block system between the initial state and the equilibrium state? (c) what is the change in the entropy of the two-block system? the heat capacities of copper and lead are 386 j/kg·k and 128 j/kg·k, respectively.