Enormous numbers of microwave photons are needed to warm macroscopic samples of matter. A portion of soup containing $252 \mathrm{~g}$ of water is heated in a microwave oven from $20 .^{\circ} \mathrm{C}$ to $98^{\circ} \mathrm{C}$, with radiation of wavelength $1.55 \times 10^{-2} \mathrm{~m}$. How many photons are absorbed by the water in the soup?