A microwave oven heats by radiating food with microwave radiation, which is absorbed by the food and converted to heat. Suppose an oven’s radiation wavelength
is 12.5 cm. A container with 0.250 L of water was placed in the oven, and the
temperature of the water rose from 20.0°C to 100.0°C. How many photons of this
microwave radiation were required? Assume that all the energy from the radiation was
used to raise the temperature of the water.

5.283x10^28

Explanation:

Each photon emits an energy of hf, where f is the frequency and h being planck's constant.

The heat required to raise the temperature of water from 20°C to 100°C is

Q = mS(dT)

= (density of water)(volume of water)(4200J/K)(80K)

= (10^3 kg/m^3)(0.25x10^-3 m^3)(4200J)(80)

= 84000J

Energy of each photon having wavelength 12.5x10^-2 m is

(6.62x10^-34)((3x10^8)/(12.5x10^-2)) = 1.59x10^-24J

Thus, the number of photons required are 84000/(1.59x10^-24)

= 5.2830x10^28.

Hope the explanation is sufficient.

because u need two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei to form isotopes.

so since they all have the same shape? i mean maybe because m& m and reeses are both chocolates