Question

A container with 0.485 L of water is placed into microwave and is then radiated with electromagnetic energy that has a wavelength of 14.1 cm. The temperature of the water then rose by 69.9 °C. Calculate the number of photons that were absorbed by the water. Assume water has a density of 1.00 g·mL–1 and its specific heat is 4.184 J·g–1·°C–1

Answer 1

Calculate the energy (J) increase due to heating.
Then:
Use energy per photon = h f = (Planck's constant)(frequency)
frequency = (speed of light)/(wavelength)

Divide: energy gain/energy per photon = number of photons