Chapter 6, Problem 10E

Photons of infrared radiation are responsible for much of the warmth we feel when holding our hands before a fire. These photons will also warm other objects. How many infrared photons with a wavelength of $1.5\times {10}^{-6}$ m must be absorbed by the water to warm a cup of water (175 g) from 25.0 °C to 40 °C?