Hey jiskha.
Microwave ovens emit microwave radiation that is absorbed by water. The absorbed radiation is converted to heat that is transferred to other components of the food. Suppose that the microwave radiation has a wavelength of 12.7 cm. How many photons are required to heat 200. mL of coffee from 21°C to 63°C?
I have no clue where to start.
See your later post.
To determine the number of photons required to heat the coffee, we first need to understand the steps involved in the calculation.
1. Calculate the amount of heat required to heat the coffee:
The formula to calculate the heat, Q, is given by:
Q = mcΔT
Where:
- m is the mass of the substance (coffee) in grams
- c is the specific heat capacity of the substance (coffee), which is approximately 4.18 J/g·°C
- ΔT is the change in temperature (final temperature - initial temperature) in °C.
2. Convert the mass of the coffee to grams:
The provided volume of the coffee is given in milliliters (mL). Since 1 mL of water is equal to 1 gram, we can directly use 200 grams as the mass.
3. Calculate the energy per photon:
The energy per photon, E, can be determined using the equation:
E = hc/λ
Where:
- h is Planck's constant (6.626 x 10^-34 J·s)
- c is the speed of light (2.998 x 10^8 m/s)
- λ is the wavelength of the microwave radiation in meters.
4. Calculate the total energy required to heat the coffee:
The total energy (in joules) required to heat the coffee can be calculated by multiplying the energy per photon by the number of photons:
E_total = E x N
Where N is the number of photons.
5. Finally, calculate the number of photons:
Divide the total energy required to heat the coffee by the energy per photon:
N = E_total / E
Let's break down the calculation steps and find the number of photons required.